U.S. patent application number 17/251157 was filed with the patent office on 2021-09-09 for method and wireless communication system for handling timer operation.
The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Anil AGIWAL, Pravjyot Singh DEOGUN, Abhishek Kumar SINGH.
Application Number | 20210282187 17/251157 |
Document ID | / |
Family ID | 1000005595865 |
Filed Date | 2021-09-09 |
United States Patent
Application |
20210282187 |
Kind Code |
A1 |
AGIWAL; Anil ; et
al. |
September 9, 2021 |
METHOD AND WIRELESS COMMUNICATION SYSTEM FOR HANDLING TIMER
OPERATION
Abstract
The present disclosure relates to a communication method and
system for converging a 5.sup.th-Generation (5G) communication
system for supporting higher data rates beyond a
4.sup.th-Generation (4G) system with a technology for Internet of
Things (IoT). The present disclosure may be applied to intelligent
services based on the 5G communication technology and the
IoT-related technology, such as smart home, smart building, smart
city, smart car, connected car, health care, digital education,
smart retail, security and safety services. Accordingly, the
embodiments herein disclose a method for handling a timer operation
in a wireless communication system (300). The method includes
receiving, by a UE (100), a signaling message from a base station
(200). The signaling message includes an information about acquired
COT of the base station (200). Further, the method includes
indicating, by the UE (100), about the acquired COT to a MAC layer
from a physical layer. The physical layer indicates one of the base
station (200) has acquired the COT for transmission and the base
station (200) has missed a transmission opportunity due to a LBT
failure.
Inventors: |
AGIWAL; Anil; (Bangalore,
IN) ; SINGH; Abhishek Kumar; (Bangalore, IN) ;
DEOGUN; Pravjyot Singh; (Bangalore, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si, Gyeonggi-do |
|
KR |
|
|
Family ID: |
1000005595865 |
Appl. No.: |
17/251157 |
Filed: |
June 13, 2019 |
PCT Filed: |
June 13, 2019 |
PCT NO: |
PCT/KR2019/007141 |
371 Date: |
December 10, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 74/0841 20130101;
H04W 74/008 20130101; H04W 80/02 20130101; H04W 28/0278 20130101;
H04W 76/28 20180201; H04W 74/0816 20130101 |
International
Class: |
H04W 74/08 20060101
H04W074/08; H04W 80/02 20060101 H04W080/02; H04W 74/00 20060101
H04W074/00; H04W 76/28 20060101 H04W076/28; H04W 28/02 20060101
H04W028/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 13, 2018 |
IN |
201841022151 |
Jun 12, 2019 |
IN |
201841022151 |
Claims
1. A method for handling a timer operation in a wireless
communication system (300), comprising: determining, by a base
station (200), whether a Channel Occupancy Time (COT) is started or
ongoing; and performing, by the base station (200), one of: sending
a COT active indication to a User Equipment (UE) (100) indicating
that the base station (200) has acquired the COT for transmission
in response to determining that the COT is started or ongoing, and
sending a COT inactive indication to the UE (100) indicating that
the base station (200) has missed a transmission opportunity due to
a listen-before-talk (LBT) failure in response to determining that
the COT is not started or ongoing.
2. The method of claim 1, wherein one of the COT active indication
and the COT inactive indication are sent to the UE (100), from the
base station (200), based on a signaling message, wherein the
signaling message comprises at least one of a layer-1 message, a
Medium Access Control-Control Element (MAC CE) message, and a Radio
Resource Control (RRC) message.
3. The method of claim 1, wherein the COT inactive indication is
send to the UE (100), when the base station (200) has acquired a
channel using a short LBT, but the base station (200) is
unsuccessful to acquire the channel using a long LBT.
4. A method for handling a timer operation in a wireless
communication system (300), comprising: receiving, by a User
Equipment (UE) (100), a signaling message from a base station
(200), wherein the signaling message comprises an information about
acquired channel occupancy time (COT) of the base station (200);
and indicating, by the UE (100), about the acquired COT information
to a medium Access control (MAC) layer from a physical layer,
wherein the physical layer indicates one of the base station (200)
has acquired the COT for transmission and the base station (200)
has missed a transmission opportunity due to a listen-before-talk
(LBT) failure.
5. The method of claim 4, wherein the signaling message comprises
at least one of a layer-1 message, a Medium Access Control-Control
Element (MAC CE) message, and a Radio Resource Control (RRC)
message, and wherein the indication of the signaling message from
the base station (200) containing the information about the
acquired COT is based on at least one of a search space
configuration, a CORESET configuration, and a monitoring time
configuration.
6. The method of claim 5, wherein the search space configuration
comprises at least one of a time resource for a downlink signal
monitoring, an information about at least one of Downlink Control
Information (DCI) format, a Synchronization Signal Block (SSB), a
Channel State Information Reference Signal (CSI-RS), and a preamble
transmission to be monitored by the UE (100), wherein the search
space configuration is provided for a Physical Downlink Control
Channel (PDCCH) monitoring corresponding to at least one of a
Random Access Response (RAR) and a Physical Uplink Shared Channel
(PUSCH), wherein the UE (100) is configured to monitor one of a
separate DCI format, a SSB, a CSI-RS resource, and a preamble
transmission from a cell within the search space configuration, and
wherein the monitoring time configuration comprises at least one of
time resources, time periodicity, offset and duration for
monitoring at least one of a Synchronization Signal Block (SSB)
parameter, a Channel State Information Reference Signal (CSI-RS),
and a preamble information.
7. The method of claim 4, further comprises: detecting, by the UE
(100), that an event to start a MAC timer (140) is satisfied;
starting, by the UE (100), a COT timer (150) instead of the MAC
timer (140) in response to the event to start the COT timer is
satisfied; receiving, by the UE (100), a COT active indication
indicating that the base station (200) has acquired the COT for
transmission; stopping the COT timer (150) and starting the MAC
timer (140) based on the COT active indication, stopping or
pausing, by the UE (100), the MAC timer (140) and resuming or
restarting the COT timer (150) when the UE (100) receives a COT
inactive indication indicating that the base station (200) has
missed the transmission opportunity based on the LBT failure; and
stopping or pausing, by the UE (100), the COT timer (150) and
resuming or restarting the MAC timer (140) based on the COT active
indication, wherein the COT timer (150) is provided at least one of
a common configuration for each MAC timer (140) and a separate
configuration for each MAC timer (140), wherein the MAC timer (140)
corresponding to same MAC procedure can have a same independent
configuration, and wherein the common configuration is provided
based on at least one of a per serving cell, a per bandwidth part,
and a per MAC entity basis, and wherein a configuration of the COT
timer (150) is modified through one of a RRC signalling message, a
MAC CE based signalling message, and a DCI based signalling
message.
8. The method of claim 4, further comprises: detecting, by the UE
(100), a failure event due to the LBT failure on expiry of a COT
timer (150), wherein the failure event is a Random Access Response
reception failure event, a contention resolution failure event, a
scheduling request procedure failure event, a Discontinuous
Reception (DRX) procedure failure event, and a buffer status
reporting (BSR) procedure failure event, wherein the UE (100)
performs that at least one of a PREAMBLE_POWER_RAMPING_COUNTER is
not incremented and the UE (100) de-prioritizes a PRACH
transmission using one of the SSB and the CSI-RS based RACH
resources in case of a RAR failure due to the LBT failure, wherein
the UE (100) triggers a scheduling request (SR) and increments
scheduling request (SR) counter by a predefined value, when the UE
(100) handles a SR failure based on the LBT failure, and wherein
the UE (100) maintains a counter value and waits for a counter to
exceed an RRC configured threshold value prior to increasing a SR
counter and triggering a SR or triggering a RACH, when the UE (100)
handles a SR failure based on the LBT failure.
9. The method of claim 4, further comprises: restarting, by the UE
(100) the MAC timer (140) upon reception of a COT inactive
indication, wherein the UE (100) starts a ra-response window based
on one of the MAC layer instructs the physical layer to perform a
PRACH transmission, the physical layer starts transmission on a
first PRACH occasion, and an end of PRACH transmission performed by
the physical layer, wherein the UE (100) starts a ra-Contention
Resolution timer based on at least one of the MAC layer instructs
the physical layer to perform a RRC connection request message
transmission, the physical layer starts transmission on a
symbol/slot of the RRC connection request message, and an end of
RRC connection request message transmission performed by the
physical layer.
10. A base station (200) for handling a timer operation in a
wireless communication system (300), comprising: a memory (230);
and a processor (210), coupled with the memory (230), configured
to: determine whether a Channel Occupancy Time (COT) is started or
ongoing; and perform one of: send an COT active indication to a
User Equipment (UE) (100) indicating that the base station (200)
has acquired the COT for transmission in response to determining
that the COT is started or ongoing, and send an COT inactive
indication to the UE (100) indicating that the base station (200)
has missed a transmission opportunity due to a listen-before-talk
(LBT) failure in response to determining that the COT is not
started or ongoing.
11. The base station (200) of claim 10, wherein the COT active
indication or the COT inactive indication are sent to the UE (100)
based on a signaling message from the base station (200), wherein
the signaling message comprises at least one of a layer-1 message,
a Medium Access Control-Control Element (MAC CE) message, and a
Radio Resource Control (RRC) message, and wherein the COT inactive
indication is send to the UE (100), when the base station (200)
acquires a channel using a short LBT, but the base station (200) is
unsuccessful to acquire the channel using a long LBT.
12. A User Equipment (UE) (100) for handling a timer operation in a
wireless communication system (300), comprising: a memory (130);
and a processor (110), coupled with the memory (130), configured
to: receive a signaling message from a base station (200), wherein
the signaling message comprises an information about acquired
channel occupancy time (COT) of the base station (200); and
indicate about the acquired COT information to a medium Access
control (MAC) layer from a physical layer, wherein the physical
layer indicates one of the base station (200) has acquired the COT
for transmission using a COT active indication and the base station
(200) has missed a transmission opportunity due to a
listen-before-talk (LBT) failure using a COT inactive
indication.
13. The UE (100) of claim 12, wherein the signaling information
comprises at least one of a layer-1 message, a Medium Access
Control-Control Element (MAC CE) message, and a Radio Resource
Control (RRC) message, wherein the indication of the signaling
message from the base station (200) containing information about
the acquired COT of the base station (200) is based on at least one
of a search space configuration, a CORESET configuration, and a
monitoring time configuration, wherein the search space
configuration comprises at least one of a time resource for a
downlink signal monitoring, an information about at least one of
Downlink Control Information (DCI) format, a Synchronization Signal
Block (SSB), a Channel State Information Reference Signal (CSI-RS),
and a preamble transmission to be monitored by the UE (100),
wherein the search space configuration is provided for a Physical
Downlink Control Channel (PDCCH) monitoring corresponding to at
least one of a Random Access Response (RAR) and a Physical Uplink
Shared Channel (PUSCH), wherein the UE (100) is configured to
monitor one of a separate DCI format, a SSB, CSI-RS resource, and a
preamble transmission from a cell within the search space
configuration, and wherein the monitoring time configuration
comprises at least one of a time resource, time periodicity, offset
and duration for monitoring at least one of a Synchronization
Signal Block (SSB) parameters, Channel State Information Reference
Signal (CSI-RS), and preamble information.
14. The UE (100) of claim 12, wherein the processor (110) is
configured to: detect that an event to start a MAC timer (140) is
satisfied; start a COT timer (150) instead of the MAC timer (140)
in response to the event to start the COT timer is satisfied;
receive an COT active indication indicating that the base station
(200) has acquired the COT for transmission; and stop the COT timer
(150) and start the MAC timer (140) based on the COT active
indication, wherein the processor (110) is configured to: stop or
pause the MAC timer (140) and resume or restart the COT timer
(150), when the UE (100) receives a COT inactive indication
indicating that the base station (200) has missed the transmission
opportunity due to a LBT failure; and stop or pause the COT timer
(150) and resume or restart the MAC timer (140) based on the COT
active indication, wherein the COT timer (150) is provided at least
one of a common configuration for each MAC timer (140) and a
separate configuration for each MAC timer (140) wherein the MAC
timer (140) corresponding to same MAC procedure can have the same
independent configuration, and wherein the common configuration is
provided based on at least one of a per serving cell, a per
bandwidth part, and a per MAC entity basis, and wherein the
configuration of the COT timer (150) is modified through one of a
RRC signalling message, a MAC CE based signalling message, and a
DCI based signalling message.
15. The UE (100) of claim 12, wherein the processor (110) is
configured to detect a failure event due to the LBT failure on
expiry of a COT timer (150), and to restart the MAC timer (140)
upon reception of the COT inactive indication, wherein the failure
event is a Random Access Response reception failure event, a
contention resolution failure event, a scheduling request procedure
failure event, a Discontinuous Reception (DRX) procedure failure
event, and a buffer status reporting (BSR) procedure failure event,
wherein the UE (100) starts a ra-response window based on one of
the MAC layer instructs the physical layer to perform a PRACH
transmission, the physical layer starts transmission on a first
PRACH occasion, and an end of PRACH transmission performed by the
physical layer, wherein the UE performs that at least one of a
PREAMBLE_POWER_RAMPING_COUNTER is not incremented and the UE
de-prioritizes the PRACH transmission using the SSB/CSI-RS based
RACH Resources in case of a RAR failure due to the LBT failure,
wherein the UE (100) starts ra-contention window timer based on at
least one of the MAC layer instructs the physical layer to perform
a RRC connection message, the physical layer starts transmission on
a symbol/slot of the RRC connection request message, an end of the
RRC connection request message transmission performed by the
physical layer, wherein the UE (100) triggers a scheduling request
(SR) and increments scheduling request (SR) counter by a predefined
value, when the UE (100) handles a SR failure based on the LBT
failure, and wherein the UE (100) maintains a counter value and
waits for a counter to exceed an RRC configured threshold value
prior to increasing a SR counter and triggering a SR or triggering
a RACH, when the UE (100) handles a SR failure based on the LBT
failure.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a 371 National Stage of International
Application No. PCT/KR2019/007141, filed Jun. 13, 2019, which
claims priority to Indian Provisional Patent Application No.
201841022151, filed Jun. 13, 2018, and Indian Non-Provisional
Patent Application No. 201841022151, filed Jun. 12, 2019, the
disclosures of which are herein incorporated by reference in their
entirety.
BACKGROUND
1. Field
[0002] The present disclosure relates to a method and wireless
communication system for handling timer operation, and more
specifically relates to a management of a medium access control
(MAC) layer timers for a new radio (NR) unlicensed operation which
work using a listen-before-talk in the wireless communication
system.
2. Description of Related Art
[0003] To meet the demand for wireless data traffic having
increased since deployment of 4G communication systems, efforts
have been made to develop an improved 5G or pre-5G communication
system. Therefore, the 5G or pre-5G communication system is also
called a `Beyond 4G Network` or a `Post LTE System`. The 5G
communication system is considered to be implemented in higher
frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish
higher data rates. To decrease propagation loss of the radio waves
and increase the transmission distance, the beamforming, massive
multiple-input multiple-output (MIMO), Full Dimensional MIMO
(FD-MIMO), array antenna, an analog beam forming, large scale
antenna techniques are discussed in 5G communication systems. In
addition, in 5G communication systems, development for system
network improvement is under way based on advanced small cells,
cloud Radio Access Networks (RANs), ultra-dense networks,
device-to-device (D2D) communication, wireless backhaul, moving
network, cooperative communication, Coordinated Multi-Points
(CoMP), reception-end interference cancellation and the like. In
the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding
window superposition coding (SWSC) as an advanced coding modulation
(ACM), and filter bank multi carrier (FBMC), non-orthogonal
multiple access(NOMA), and sparse code multiple access (SCMA) as an
advanced access technology have been developed.
[0004] The Internet, which is a human centered connectivity network
where humans generate and consume information, is now evolving to
the Internet of Things (IoT) where distributed entities, such as
things, exchange and process information without human
intervention. The Internet of Everything (IoE), which is a
combination of the IoT technology and the Big Data processing
technology through connection with a cloud server, has emerged. As
technology elements, such as "sensing technology", "wired/wireless
communication and network infrastructure", "service interface
technology", and "Security technology" have been demanded for IoT
implementation, a sensor network, a Machine-to-Machine (M2M)
communication, Machine Type Communication (MTC), and so forth have
been recently researched. Such an IoT environment may provide
intelligent Internet technology services that create a new value to
human life by collecting and analyzing data generated among
connected things. IoT may be applied to a variety of fields
including smart home, smart building, smart city, smart car or
connected cars, smart grid, health care, smart appliances and
advanced medical services through convergence and combination
between existing Information Technology (IT) and various industrial
applications.
[0005] In line with this, various attempts have been made to apply
5G communication systems to IoT networks. For example, technologies
such as a sensor network, Machine Type Communication (MTC), and
Machine-to-Machine (M2M) communication may be implemented by
beamforming, MIMO, and array antennas. Application of a cloud Radio
Access Network (RAN) as the above-described Big Data processing
technology may also be considered to be as an example of
convergence between the 5G technology and the IoT technology.
SUMMARY
[0006] An NR operation in an unlicensed band requires a NB/user
Equipment (UE) to perform a Listen before Talk (LBT) procedure
before any transmission. If any other device (e.g., other UE) is
using an unlicensed spectrum at that point of time, it is seen as
an LBT Failure and the UE/NB cannot transmit until the LBT passes.
As a result of the NB can miss transmission opportunities for
critical transmissions like Physical Downlink Control Channel
(PDCCH) Transmissions. Random Access channel (RACH) Procedure
requires the UE to monitor for downlink assignment addressed to a
Random Access Radio Network Temporary Identifier (RA-RNTI)/cell
Radio Network Temporary Identifier (C-RNTI) (Random Access
Response) for the duration of ra-ResponseWindow after transmission
of a RACH preamble (as per 3GPP TS 38.321). If a response is not
received within a window then it is assumed that the RACH preamble
decoding has failed at the NB or RACH preamble did not reach the NB
and the RACH failure is assumed. However, when the NR operates in
the unlicensed band, the downlink assignment addressed to the
RA-RNTI/C-RNTI may be delayed because of the LBT failures at the
NB. Hence if the UE doesn't receive the appropriate downlink
assignment within the window, the UE cannot differentiate whether
it is the RACH Failure or the LBT Failure at the NB.
[0007] If the UE is successfully able to transmit message 3 (i.e.,
Msg3), then the UE monitors the PDCCH for a downlink assignment
addressed to its TC-RNTI/C-RNTI and successful decoding of a
message 4 (i.e., Msg4) (if applicable) as per 3GPP TS 38.321, for a
duration of ra-ContentionResolutionTimer. If an appropriate
downlink assignment and successfully decoded Msg4 (if applicable)
is not received in the duration of ra-ContentionResolutionTimer, it
is assumed that contention resolution has failed and the RACH
failure is assumed. However, when the NR operates in the unlicensed
band the downlink assignment addressed to TC-RNTI/C-RNTI and/or
successfully decoded the Msg4 (if applicable) may be delayed
because of the LBT failures at the NB. Hence, if the UE doesn't
receive the appropriate downlink assignment within the window, the
UE cannot differentiate whether it is the RACH Failure or the LBT
Failure at the NB. Due to possibility of the LBT Failure based
absence of appropriate DCI or downlink transmission required for a
RAR/Contention resolution the UE cannot decide whether it is due to
the RACH procedure failure or the LBT Failure.
[0008] Similar arguments as above are valid for DRX operation as
well, absence of PDCCH corresponding to the UE can be because of
either there is no downlink data transmission for the UE or because
of inability of the NB to send PDCCH due to the LBT failures.
Similarly for Scheduling Request (SR)/Buffer Status Report (BSR)
procedures absence of PDCCH containing uplink grant, after BSR/SR
has been sent can be due can be because of either there is SR/BSR
was not decoded at NB or NB doesn't want to schedule or because of
inability of NB to send PDCCH due to the LBT failures.
[0009] Thus, it is desired to address the above mentioned
disadvantages or other shortcomings or at least provide a useful
alternative.
[0010] In an embodiment, the COT active indication or the COT
inactive indication are sent to the UE, from the base station
(200), based on a signaling message. The signaling message includes
at least one of a layer-1 message, a Medium Access Control-Control
Element (MAC CE) message, and a Radio Resource Control (RRC)
message.
[0011] In an embodiment, the COT inactive indication is send to the
UE, when the base station acquires a channel using a short LBT, but
the base station is unsuccessful to acquire the channel using a
long LBT.
[0012] Accordingly, the embodiments herein disclose a method for
handling a timer operation in a wireless communication system. The
method includes receiving, by a UE, a signaling message from a base
station. The signaling message includes an information about
acquired COT of the base station. Further, the method includes
indicating, by the UE, about the acquired COT information to a MAC
layer from a physical layer. The physical layer indicates one of
the base station has acquired the COT for transmission and the base
station has missed a transmission opportunity due to a LBT
failure.
[0013] The timer operation can correspond to any timer in the MAC
layer corresponding to a RAR, a CR, a SR, DRX, and a BSR.
[0014] In an embodiment, the information about the acquired COT of
the base station is indicated based on at least one of a search
space configuration, a CORESET configuration, and a monitoring time
configuration.
[0015] In an embodiment, at least one of the search space
configuration, the CORESET configuration, and the monitoring time
configuration is provided for the UE to monitor for base station
transmissions providing information about the acquired COT.
[0016] In an embodiment, the search space configuration comprises
at least one of a time resource for a downlink signal monitoring,
an information about at least one of Downlink Control Information
(DCI) format, a Synchronization Signal Block (SSB), a Channel State
Information Reference Signal (CSI-RS), and a preamble transmission
to be monitored by the UE.
[0017] In an embodiment, the search space configuration is provided
for a Physical Downlink Control Channel (PDCCH) monitoring
corresponding to at least one of a RAR, a PDSCH and a PUSCH. In an
embodiment, the monitoring time configuration comprises at least
one of a Synchronization Signal Block (SSB) parameters, Channel
State Information Reference Signal (CSI-RS), and preamble
information, wherein the UE (100) is configured to monitor one of a
separate DCI format, a SSB, a CSI-RS resource, and a preamble
transmission from a cell within the search space configuration.
[0018] In an embodiment, the monitoring time configuration
comprises at least one of time resources, time periodicity, offset
and duration for monitoring at least one of a Synchronization
Signal Block (SSB) parameter, a Channel State Information Reference
Signal (CSI-RS), and a preamble information.
[0019] In an embodiment, the method includes detecting, by the UE,
that an event to start a MAC timer is satisfied. Further, the
method includes starting, by the UE, the COT timer instead of the
MAC timer in response to the event to start the COT timer is
satisfied. Further, the method includes receiving, by the UE, a COT
active indication indicating that the base station acquires the COT
for transmission. Further, the method includes stopping the COT
timer and starting the MAC timer based on the COT active
indication.
[0020] In an embodiment, the method includes stopping or pausing,
by the UE, the MAC timer and resuming and restarting the COT timer
when the UE receives a COT inactive indication indicating that the
base station has missed a transmission opportunity due to a LBT
failure. Further, the method includes stopping or pausing, by the
UE, the COT timer and resuming or restarting the MAC timer based on
the COT active indication.
[0021] In an embodiment, the event corresponds to one of receiving
a Synchronization Signal Block (SSB) transmission information, a
SSB transmission information from the base station corresponding to
a SSB index associated with a transmitted Physical Random Access
Channel (PRACH), a Channel State Information Reference Signal
(CSI-RS) transmission from the base station corresponding to a
serving cell, a CSI-RS transmission from the base station
corresponding to the CSI-RS index of the serving cell associated
with a transmitted PRACH, a Physical Downlink Control Channel
(PDCCH) identified by a cell common Radio Network Temporary
Identifier (RNTI) value, a preamble transmission from the base
station indicating one of a start COT, an end COT, and an ongoing
COT for the serving cell of the base station, and base station
transmission according to the monitoring criteria defined for the
MAC timer.
[0022] In an embodiment, the COT timer (150) is provided at least
one of a common configuration for each MAC timer (140) and a
separate configuration for each MAC timer (140) wherein the MAC
timer (140) corresponding to same MAC procedure can have the same
independent configuration, and wherein the common configuration is
provided based on at least one of a per serving cell, a per
bandwidth part, a per MAC entity basis.
[0023] In an embodiment, the configuration of the COT timer is
modified through one of a RRC signalling message, a MAC CE based
signalling message, a DCI based signalling message.
[0024] In an embodiment, the method includes detecting, by the UE,
a failure event due to the LBT failure on expiry of a COT timer,
wherein the failure event is a Random Access Response reception
failure event, a contention resolution failure event, a scheduling
request procedure failure event, a DRX procedure failure event, and
a BSR procedure failure event.
[0025] In an embodiment, the method includes restarting, by the UE
the MAC timer upon reception of a COT inactive indication.
[0026] In an embodiment, the UE starts a ra-response window based
on one of the MAC layer instructs the physical layer to perform a
PRACH transmission, the physical layer starts transmission on a
first PRACH occasion, an end of PRACH transmission performed by the
physical layer.
[0027] In an embodiment, the UE performs that at least one of a
PREAMBLE_POWER_RAMPING_COUNTER is not incremented and the UE
de-prioritizes a PRACH transmission using one of the SSB and the
CSI-RS based RACH resources in case of a RAR failure due to LBT
failure.
[0028] In an embodiment, the UE starts a ra-Contention Resolution
timer based on at least one of the MAC layer instructs the physical
layer to perform a RRC connection request message transmission, the
physical layer starts transmission on a symbol/slot of the RRC
connection request message, and an end of RRC connection request
message transmission performed by the physical layer.
[0029] In an embodiment, the UE triggers a scheduling request (SR)
and increments scheduling request (SR) counter by a predefined
value, when the UE handles a SR failure based on the LBT
failure.
[0030] In an embodiment, the UE maintains a counter value and waits
for a counter to exceed an RRC configured threshold value prior to
increasing a SR counter and triggering a SR or triggering a RACH,
when the UE handles a SR failure based on the LBT failure.
[0031] Accordingly, the embodiments herein disclose a base station
for handling a timer operation in a wireless communication system.
The base station includes a processor coupled with a memory. The
processor is configured to determine whether a COT is started or
ongoing. The processor is configured to perform one of send an COT
active indication to a UE indicating that the base station has
acquired the COT for transmission in response to determine that the
COT is started or ongoing, and send an COT inactive indication to
the UE indicating that the base station has missed a transmission
opportunity due to a listen-before-talk (LBT) failure in response
to determine that the COT is not started or ongoing.
[0032] Accordingly, the embodiments herein disclose a UE for
handling a timer operation in a wireless communication system. The
UE includes a processor coupled with a memory. The processor is
configured to receive a signaling message from a base station. The
signaling message includes an information about acquired COT of the
base station. The processor is configured to indicate about the
acquired COT to a MAC layer from a physical layer. The physical
layer indicates one of the base station acquires the COT for
transmission and the base station has missed a transmission
opportunity due to a LBT failure.
[0033] These and other aspects of the embodiments herein will be
better appreciated and understood when considered in conjunction
with the following description and the accompanying drawings. It
should be understood, however, that the following descriptions,
while indicating preferred embodiments and numerous specific
details thereof, are given by way of illustration and not of
limitation. Many changes and modifications may be made within the
scope of the embodiments herein without departing from the spirit
thereof, and the embodiments herein include all such
modifications.
[0034] The principal object of the embodiments herein is to provide
a method and system for handling a timer operation in a wireless
communication system. Accordingly, the embodiments herein disclose
a method for handling a timer operation in a wireless communication
system. The method includes determining, by a base station, whether
a COT is started or ongoing. Further, the method includes
performing, by the base station, one of: sending an COT active
indication to a UE indicating that the base station has acquired
the COT for transmission in response to determining that the COT is
started or ongoing, and sending an COT inactive indication to the
UE indicating that the base station has missed a transmission
opportunity due to a listen-before-talk (LBT) failure in response
to determining that the COT is not started or ongoing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] This method is illustrated in the accompanying drawings,
throughout which like reference letters indicate corresponding
parts in the various figures. The embodiments herein will be better
understood from the following description with reference to the
drawings, in which:
[0036] FIG. 1A is an overview of a wireless communication system
for handling a timer operation, according to the embodiments as
disclosed herein;
[0037] FIG. 1B is a block diagram of a processor included in a UE,
according to the embodiments as disclosed herein;
[0038] FIG. 1C is a block diagram of a processor included in a base
station, according to the embodiments as disclosed herein;
[0039] FIG. 2A is a schematic diagram illustrating a timer handling
in a non-adaptive procedure, according to the embodiments as
disclosed herein;
[0040] FIG. 2B is a schematic diagram illustrating a timer handling
in an adaptive procedure, according to the embodiments as disclosed
herein;
[0041] FIG. 2C is a schematic diagram illustrating a network
indication based timer restart, according to the embodiments as
disclosed herein;
[0042] FIG. 3 is a flow chart illustrating a method, implemented by
the base station, for handling the timer operation in the wireless
communication system, according to the embodiments as disclosed
herein; and
[0043] FIG. 4 is a flow chart illustrating a method, implemented by
the UE, for handling the timer operation in the wireless
communication system, according to the embodiments as disclosed
herein.
DETAILED DESCRIPTION
[0044] The embodiments herein and the various features and
advantageous details thereof are explained more fully with
reference to the non-limiting embodiments that are illustrated in
the accompanying drawings and detailed in the following
description. Descriptions of well-known components and processing
techniques are omitted so as to not unnecessarily obscure the
embodiments herein. Also, the various embodiments described herein
are not necessarily mutually exclusive, as some embodiments can be
combined with one or more other embodiments to form new
embodiments. The term "or" as used herein, refers to a
non-exclusive or, unless otherwise indicated. The examples used
herein are intended merely to facilitate an understanding of ways
in which the embodiments herein can be practiced and to further
enable those skilled in the art to practice the embodiments herein.
Accordingly, the examples should not be construed as limiting the
scope of the embodiments herein.
[0045] As is traditional in the field, embodiments may be described
and illustrated in terms of blocks which carry out a described
function or functions. These blocks, which may be referred to
herein as managers, units, modules, hardware components or the
like, are physically implemented by analog and/or digital circuits
such as logic gates, integrated circuits, microprocessors,
microcontrollers, memory circuits, passive electronic components,
active electronic components, optical components, hardwired
circuits and the like, and may optionally be driven by firmware and
software. The circuits may, for example, be embodied in one or more
semiconductor chips, or on substrate supports such as printed
circuit boards and the like. The circuits constituting a block may
be implemented by dedicated hardware, or by a processor (e.g., one
or more programmed microprocessors and associated circuitry), or by
a combination of dedicated hardware to perform some functions of
the block and a processor to perform other functions of the block.
Each block of the embodiments may be physically separated into two
or more interacting and discrete blocks without departing from the
scope of the disclosure. Likewise, the blocks of the embodiments
may be physically combined into more complex blocks without
departing from the scope of the disclosure.
[0046] The following terminologies are used in the patent
disclosure.
[0047] 1. NR: New Radio. This term is synonymous to 5G.
[0048] 2. LTE: Long Term Evolution. This term is synonymous to
4G.
[0049] 3. RACH: Random access procedure done by a UE.
[0050] 4. eNB: enhanced NodeB (LTE NodeB).
[0051] 5. gNB: 5G NodeB.
[0052] 6. RAR--Random access response.
[0053] 7. PDCCH--Physical Downlink Control Channel.
[0054] 8. DCI--Downlink Control Information.
[0055] 9. SSB: Synchronization Signal Block. One synchronization
signal block contains Primary Synchronization Signal, Secondary
Synchronization Signal and Physical Broadcast Channel
transmission.
[0056] 10. LBT: Listen before talk. Before initiating transmission
on an unlicensed channel, UE/NB is required to check if the
unlicensed channel is being used for communication by any other
device in vicinity. If no such device is found communicating in the
unlicensed channel for a certain period of time, then UE/NB can
initiate transmission on the unlicensed channel.
[0057] 11. COT: Channel Occupancy Time. It the amount of time that
a UE or NB can reserve the unlicensed channel for continuous data
or control transmission. After UE/NB acquires the unlicensed
channel using LBT operation. It can perform transmission over the
unlicensed channel for the time indicated by Channel Occupancy
Time. This transmission duration can also be referred to as
transmission burst.
[0058] Accordingly, the embodiments herein provides a method for
handling a timer operation in a wireless communication system. The
method includes receiving, by a UE, a signaling message from a base
station. The signaling message includes an information about
acquired COT of the base station. Further, the method includes
indicating, by the UE, about the acquired COT to a MAC layer from a
physical layer. The physical layer indicates one of the base
station has acquired the COT for transmission and the base station
has missed a transmission opportunity due to a LBT failure.
[0059] In one embodiment, based on some radio signaling between the
UE and the NB, lower layers (e.g. physical layer) of the UE will
provide one of the two indications to UE's MAC Layer (dlCOTActive:
NB is able to acquire COT for transmission and dlCOTInactive: NB
has missed a transmission opportunity due to LBT Failures). The
base station can transmit a Layer-1 (L1) message or Medium Access
Control-Control Element (MAC CE) or Radio Resource Control (RRC)
message which contains indication about acquired COT of the base
station. In an example, UE's physical layer after receiving a
downlink transmission from a serving cell (e.g. SSB or Channel
State Indicator-Reference Signal (CSI-RS) or a PDCCH identified by
a common cell identity or a downlink preamble) can determine that
serving cell's downlink transmission burst or COT has started or
ongoing and based on which it can indicate dlCOTActive to MAC
entity. Also, the physical layer of the UE can determine the end of
serving cell's downlink transmission burst or COT based on
different methods (e.g. UE can determine end of COT based on
absence of cell common signal like SSB or CSI-RS or serving cell
indicates the end time of downlink transmission burst during
ongoing COT using SSB or a PDCCH transmission which contains
information about end time), in which case the physical layer can
indicate dlCOTInactive to the MAC entity.
[0060] In an embodiment, the UE can be provided with RRC
configuration (using system information or dedicated RRC signaling)
in order to allow the UE to monitor for base station transmissions
containing information about the acquired COT and initiate
dlCOTTimer. Following information may be contained within the
configuration.
[0061] In an embodiment, a search space configuration can be
provided for the UE to monitor for the base station transmissions
providing information about the acquired COT. The search space
configuration includes time resources (e.g. time offset,
periodicity and duration) for downlink signal monitoring and may
contain information about DCI format or information about SSB or
CSI-RS or preamble transmission to be monitored by the UE.
[0062] In another embodiment, the UE monitors the search space
configured for PDCCH monitoring corresponding to a RAR or a PDSCH
or a PUSCH, etc. Within the search space, the UE can be configured
to monitor a separate DCI format or a SSB or a CSI-RS resource or
preamble transmission from a cell. The UE can also be configured
with monitoring time occasions (e.g. time periodicity, offset,
duration) used for monitoring the given base station transmissions.
By decoding the given base station transmission (e.g.
DCI/SSB/CSI-RS/preamble), the UE can determine information about
COT acquired by the base station.
[0063] In another embodiment, separate CORESET configuration can be
provided to the UE to monitor for base station transmissions
providing information about the acquired COT. If no such
configuration is provided then, the UE uses the CORESET
configuration provided in a SIB1 associated with
ControlResourceSetId=0.
[0064] In another embodiment, the UE can be configured with
monitoring time configuration (which includes time periodicity,
offset and duration), where the UE is expected to monitor for the
base station transmissions indicating information about the
acquired COT. The configuration may also contain information about
the base station transmissions e.g. SSB parameters, CSI-RS
resources, preamble information, etc.
[0065] Referring now to the drawings, and more particularly to
FIGS. 1A through 4, where similar reference characters denote
corresponding features consistently throughout the figures, there
are shown preferred embodiments.
[0066] FIG. 1A is an overview of a wireless communication system
(300) for handling a timer operation, according to the embodiments
as disclosed herein. In an embodiment, the wireless communication
system (300) includes a UE (100) and a base station (200). The UE
(100) can be, for example but not limited to a cellular phone, a
tablet, a smart phone, a laptop, a Personal Digital Assistant
(PDA), a global positioning system, a multimedia device, a video
device, an internet of things (IoT) device, a smart watch, a game
console, an Unmanned Aerial Vehicle (UAV), an airplane, or the
like. The UE (100) may also be referred to by those skilled in the
art as a mobile station, a subscriber station, a mobile unit, a
subscriber unit, a wireless unit, a remote unit, a mobile device, a
wireless device, a wireless communications device, a mobile
subscriber station, an access terminal, a mobile terminal, a
wireless terminal, a remote terminal, a handset, a user agent, a
mobile client, or the like. The base station (200) may also be
referred to as a base transceiver station, a radio base station, a
radio transceiver, a transceiver function, a basic service set
(BSS), an extended service set (ESS), an eNB, a gNB or the
like.
[0067] In an embodiment, the UE (100) includes a processor (110), a
communicator (120), a memory (130), a MAC Timer (140) and a COT
Timer (150). The processor (110) is coupled with the communicator
(120), the memory (130), the MAC Timer (140) and the COT Timer
(150).
[0068] In an embodiment, the processor (110) is configured to
receive a signaling message from a base station (200). The
signaling message includes an information about acquired COT of the
base station (200). Further, the processor (110) is configured to
indicate about the acquired COT to a MAC layer from a physical
layer. The physical layer indicates that the base station (200)
acquires the COT for transmission or the base station (200) has
missed a transmission opportunity due to a LBT failure.
[0069] In an embodiment, the signaling information includes at
least one of a layer-1 message, a MAC CE message, and a RRC
message. In an embodiment, the information about the acquired COT
of the base station (200) is indicated based on at least one of a
search space configuration, a CORESET configuration, and a
monitoring time configuration.
[0070] In an embodiment, at least one of the search space
configuration, the CORESET configuration, and the monitoring time
configuration is provided for the UE (100) to monitor for base
station transmissions providing information about the acquired
COT.
[0071] In an embodiment, the search space configuration includes at
least one of a time resource for a downlink signal monitoring, an
information about at least one of DCI format, a SSB, a CSI-RS, and
a preamble transmission to be monitored by the UE (100).
[0072] In an embodiment, the search space configuration is provided
for a PDCCH monitoring corresponding to at least one of a RAR, a
PDSCH and a PUSCH.
[0073] In an embodiment, the monitoring time configuration includes
at least one of a SSB parameter, CSI-RS, and preamble
information.
[0074] Further, the processor (110) is configured to detect that an
event to start a COT timer (150) is satisfied and start the COT
timer (150) instead of the MAC timer (140) in response to the event
to start the COT timer is satisfied. Further, the processor (110)
is configured to receive a COT active indication indicating that
the base station (200) acquires the COT for transmission. Further,
the processor (110) is configured to stop the COT timer (150) and
start the MAC timer (140) based on the COT active indication.
[0075] Further, the processor (110) is configured to stop or pause
the MAC timer (140) and start the COT timer (150), when the UE
(100) receives a COT inactive indication indicating that the base
station (200) has missed a transmission opportunity due to a LBT
failure. Further, the processor (110) is configured to receive
another COT active indication indicating that the base station
(200) acquires the COT for transmission. Further, the processor
(110) is configured to stop the COT timer (150) and resume the MAC
timer (140) based on the COT active indication.
[0076] In an embodiment, the event corresponds to one of receiving
a Synchronization Signal Block (SSB) transmission information, a
SSB transmission information from the base station (200)
corresponding to a SSB index associated with a transmitted Physical
Random Access Channel (PRACH), a Channel State Information
Reference Signal (CSI-RS) transmission from the base station (200)
corresponding to a serving cell, a CSI-RS transmission from the
base station (200) corresponding to the CSI-RS index of the serving
cell associated with a transmitted PRACH, a Physical Downlink
Control Channel (PDCCH) identified by a cell common Radio Network
Temporary Identifier (RNTI) value, a preamble transmission from the
base station (200) indicating one of a start COT, an end COT, and
an ongoing COT for the serving cell of the base station (200), and
base station transmission according to the monitoring criteria
defined for the MAC timer.
[0077] In an embodiment, the COT timer (150) is configured based on
at least one of a serving cell, a MAC entity, a per bandwidth part,
a predefined value received from at least one a Discontinuous
Reception (DRX) timer, a random access procedure, a buffer status
reporting procedure, a power headroom reporting procedure, and a
scheduling request procedure.
[0078] In an embodiment, the configuration of the COT timer (150)
is modified through one of a RRC signalling message, a MAC CE based
signalling message, an a DCI based signalling message.
[0079] In an embodiment, the UE (100) initiates the COT timer (150)
to monitor the signaling information from the base station (200),
when at least one the UE (100) is provided with a RRC configuration
for monitoring for network transmissions containing information
about the COT, the UE (100) is monitoring for a RAR in an
unlicensed carrier, the UE (100) has performed PRACH transmission
on an unlicensed carrier, a MAC entity instructs a physical layer
to perform a PRACH transmission, the physical layer indicates a
start of PRACH transmission to the MAC layer, the physical layer
indicates an end of scheduling request transmission to the MAC
layer, the UE (100) is monitoring for a RRC connection response on
an unlicensed carrier, the UE (100) has performed a RRC connection
request transmission on an unlicensed carrier, the UE (100) is
monitoring for a PDCCH or a PDSCH transmission on the unlicensed
carrier, and the UE (100) has performed scheduling request (SR)
transmission on the unlicensed carrier.
[0080] In an embodiment, the UE (100) stops the COT timer (150),
when one the UE (100) monitors the PDCCH for downlink assignment if
a response window is running, the UE (100) monitors for PDCCH
identified by a RA-RNTI or C-RNTI in case of beam failure recovery
request, if the response window is running, the UE (100) monitors
for both PDCCH identified by the RA-RNTI or the C-RNTI in case of
beam failure recovery request and network indication containing
information about the COT, on successful reception of a RAR
addressed to the UE (100), the UE (100) initiates RAR-LBT-FAILURE
procedure, the UE (100) performs Random Access Response Failure
procedure, the UE (100) performs SR-LBT-FAILURE procedure, a
periodic BSR is triggered, and the UE (100) perform a
PERIODIC-BSR-LBT-FAILURE procedure.
[0081] The processor (110) is configured to execute instructions
stored in the memory (130) and to perform various processes. The
communicator (120) is configured for communicating internally
between internal hardware components and with external devices via
one or more networks.
[0082] The memory (130) stores instructions to be executed by the
processor 140. The memory (130) may include non-volatile storage
elements. Examples of such non-volatile storage elements may
include magnetic hard discs, optical discs, floppy discs, flash
memories, or forms of electrically programmable memories (EPROM) or
electrically erasable and programmable (EEPROM) memories. In
addition, the memory (130) may, in some examples, be considered a
non-transitory storage medium. The term "non-transitory" may
indicate that the storage medium is not embodied in a carrier wave
or a propagated signal. However, the term "non-transitory" should
not be interpreted that the memory (130) is non-movable. In some
examples, the memory (130) can be configured to store larger
amounts of information than the memory. In certain examples, a
non-transitory storage medium may store data that can, over time,
change (e.g., in Random Access Memory (RAM) or cache).
[0083] In an embodiment, the base station (200) includes a
processor (210), a communicator (220), and a memory (230). The
processor (210) is coupled with the memory (230) and the
communicator (220). The processor (210) is configured to determine
whether the COT is started or ongoing. The processor (210) is
configured to send the COT active indication to the UE (100)
indicating that the base station (200) has acquired the COT for
transmission in response to determine that the COT is started or
ongoing, and send the COT inactive indication to the UE (100)
indicating that the base station has missed the transmission
opportunity due to a LBT failure in response to determine that the
COT is not started or ongoing
[0084] In an embodiment, the COT inactive indication is send to the
UE (100), when the base station (200) acquires a channel using a
short LBT, but the base station (200) is unsuccessful to acquire
the channel using a long LBT.
[0085] The processor (210) is configured to execute instructions
stored in the memory (230) and to perform various processes. The
communicator (220) is configured for communicating internally
between internal hardware components and with external devices via
one or more networks.
[0086] The memory (230) stores instructions to be executed by the
processor (210). The memory (230) may include non-volatile storage
elements. Examples of such non-volatile storage elements may
include magnetic hard discs, optical discs, floppy discs, flash
memories, or forms of electrically programmable memories (EPROM) or
electrically erasable and programmable (EEPROM) memories. In
addition, the memory (230) may, in some examples, be considered a
non-transitory storage medium. The term "non-transitory" may
indicate that the storage medium is not embodied in a carrier wave
or a propagated signal. However, the term "non-transitory" should
not be interpreted that the memory (230) is non-movable. In some
examples, the memory (230) can be configured to store larger
amounts of information than the memory. In certain examples, a
non-transitory storage medium may store data that can, over time,
change (e.g., in Random Access Memory (RAM) or cache).
[0087] Although the FIG. 1A shows various hardware components of
the wireless communication system (300) but it is to be understood
that other embodiments are not limited thereon. In other
embodiments, the wireless communication system (300) may include
less or more number of components. Further, the labels or names of
the components are used only for illustrative purpose and does not
limit the scope of the invention. One or more components can be
combined together to perform same or substantially similar function
to handle the timer operation in the wireless communication system
(300).
[0088] FIG. 1B is a block diagram of a processor (110) included in
the UE (100), according to the embodiments as disclosed herein. In
an embodiment, the processor (110) includes a COT determiner
(110a), a timer operation indicator (110b), an event detector
(110c), a COT timer handler (110d) and a MAC timer handler
(110e).
[0089] In an embodiment, the COT determiner (110a) is configured to
receive the signaling message from the base station (200), where
the signaling message includes an information about acquired COT of
the base station (200). Further, the timer operation indicator
(110b) is configured to indicate about the timer operation to the
MAC layer from the physical layer. The physical layer indicates
that the base station (200) acquires the COT for transmission or
the base station (200) has missed a transmission opportunity due to
a LBT failure.
[0090] Further, the event detector (110c) is configured to detect
that the event to start the MAC timer (140) is satisfied. The COT
timer handler (110d) is configured to start the COT timer (150)
instead of the MAC timer (140) in response to the event to start
the COT timer is satisfied. Further, the processor (110) is
configured to receive a COT active indication indicating that the
base station (200) acquires the COT for transmission. Further, the
COT timer handler (110d) is configured to stop the COT timer (150).
The MAC timer handler (110e) is configured to start the MAC timer
(140) based on the COT active indication.
[0091] Further, the MAC timer handler (110e) is configured to stop
or pause the MAC timer (140) and start the COT timer (150) using
the COT timer handler (110d), when the UE (100) receives the COT
inactive indication indicating that the base station (200) has
missed a transmission opportunity due to a LBT failure. Further,
the COT timer handler (110d) is configured to receive another COT
active indication indicating that the base station (200) acquires
the COT for transmission. Further, the COT timer handler (110d) is
configured to stop the COT timer (150) and resume the MAC timer
(140), using the MAC timer handler (110e), based on the COT active
indication.
[0092] Although the FIG. 1B shows various hardware components of
the processor (110) but it is to be understood that other
embodiments are not limited thereon. In other embodiments, the
processor (110) may include less or more number of components.
Further, the labels or names of the components are used only for
illustrative purpose and does not limit the scope of the invention.
One or more components can be combined together to perform same or
substantially similar function to handle the timer operation in the
wireless communication system (300).
[0093] FIG. 1C is a block diagram of a processor (210) included in
the base station (200), according to the embodiments as disclosed
herein. In an embodiment, the processor (210) includes a COT
determiner (210a) and a timer operation indicator (210b).
[0094] The COT determiner (210a) is configured to determine whether
the COT is started or ongoing. The timer operation indicator (210b)
is configured to send the COT active indication to the UE (100)
indicating that the base station (200) has acquired the COT for
transmission in response to determine that the COT is started or
ongoing, and send the COT inactive indication to the UE (100)
indicating that the base station has missed a transmission
opportunity due to a LBT failure in response to determine that the
COT is not started or ongoing.
[0095] Although the FIG. 1C shows various hardware components of
the processor (210) but it is to be understood that other
embodiments are not limited thereon. In other embodiments, the
processor (210) may include less or more number of components.
Further, the labels or names of the components are used only for
illustrative purpose and does not limit the scope of the invention.
One or more components can be combined together to perform same or
substantially similar function to handle the timer operation in the
wireless communication system (300).
[0096] FIG. 2A is a schematic diagram illustrating a timer handling
in a non-adaptive procedure, according to the embodiments as
disclosed herein
[0097] Three solutions are proposed where each to adapt the
existing operation of MAC timers (140) for NR Unlicensed operation
where the UE (100) or the base station transmission (e.g. PDCCH)
can be missed/delayed due to LBT failures. One or more of MAC
timers (140) can be considered for this procedure includes
ra-ResponseWindow, bfr-ResponseWindow,
ra-ContentionResolutionTimer, drx-onDurationTimer,
drx-InactivityTimer drx-RetransmissionTimerDL,
drx-RetransmissionTimerUL, drx-ShortCycleTimer,
drx-HARQ-RTT-TimerDL, drx-HARQ-RTT-TimerUL, periodicBSR-Timer,
retxBSR-Timer, sr-ProhibitTimer, phr-PeriodicTimer, and
phr-ProhibitTimer.
[0098] In an embodiment, a radio signalling between the UE (100)
and the base station (200), lower layers (e.g. physical layers) of
the UE (100) provide one of the two indications to UE's MAC Layer:
(a) dlCOTActive--the base station (200) is able to acquire the COT
for transmission, (b) dlCOTInactive--the base station (200) has
missed a transmission opportunity due to LBT failures.
[0099] The base station (200) can transmit a Layer-1 (L1) message
or Medium Access Control-Control Element (MAC CE) or Radio Resource
Control (RRC) message which contains indication about acquired COT
of the base station (200). In an example, UE's physical layer after
receiving a downlink transmission from a serving cell (e.g. SSB or
Channel State Indicator-Reference Signal (CSI-RS) or a PDCCH
identified by a common cell identity or a downlink preamble) can
determine that serving cell's downlink transmission burst or COT
has started or ongoing and based on which the physical layer of the
UE (100) can indicate the dlCOTActive to the MAC entity. Also, the
physical layer can determine the end of serving cell's downlink
transmission burst or COT based on different methods (e.g. the UE
(100) can determine end of COT based on absence of cell common
signal like SSB or CSI-RS or serving cell indicates the end time of
downlink transmission burst during ongoing COT using a SSB or a
PDCCH transmission which contains information about end time), in
which case the physical layer can indicate dlCOTInactive to the MAC
entity. The UE (100) can be provided with a RRC configuration
(using system information or dedicated RRC signaling) in order to
allow the UE (100) to monitor for base station transmissions
containing information about the acquired COT and initiate
dlCOTTimer. Following information may be contained within the
configuration:
[0100] (1): In an embodiment, the search space configuration can be
provided for the UE (100) to monitor for base station transmissions
providing information about the acquired COT. The search space
configuration includes time resources (e.g. time offset,
periodicity and duration) for downlink signal monitoring and may
contain information about the DCI format or information about SSB
or CSI-RS or preamble transmission to be monitored by the UE
(100).
[0101] (2): In another embodiment, the UE (100) monitors search
space configured for the PDCCH monitoring corresponding to the RAR
or the PDSCH or the PUSCH, etc. Within the search space, the UE
(100) can be configured to monitor the separate DCI format or the
SSB or the CSI-RS resource or preamble transmission from the cell.
The UE (100) can also be configured with monitoring time occasions
(e.g. time periodicity, offset, duration) used for monitoring the
given base station transmissions. By decoding the given base
station transmission (e.g. DCI/SSB/CSI-RS/preamble), the UE (100)
can determine information about COT acquired by the base station
(200).
[0102] (3): In another embodiment, the separate CORESET
configuration can be provided to the UE (100) to monitor for base
station transmissions providing information about the acquired COT.
If no such configuration is provided then, UE uses the CORESET
configuration provided in the SIB1 associated with
ControlResourceSetId=0.
[0103] (4): In another embodiment, the UE (100) can be configured
with monitoring time configuration (which includes time
periodicity, offset and duration), where the UE (100) is expected
to monitor for base station transmissions indicating information
about the acquired COT. The configuration may also contain
information about the base station transmissions e.g. SSB
parameters, CSI-RS resources, preamble information, etc.
[0104] Based on this, two solutions are provided that can be
applied possible to any timer/monitoring window with minor
modifications to triggering condition.
[0105] dlCOTTimer Operation:
[0106] Non-Adaptive Approach: In one embodiment, for any
timer/monitoring window, let's say timer T, the proposed method
introduces a new timer called dlCOTTimer. The dlCOTTimer can be the
COT timer (150). The terms "dlCOTTimer" and "COT timer (150)" are
used interchangeably in the disclosure.
[0107] (1): Duration of dlCOTTimer in terms of slots or symbols or
absolute time units (e.g. in units of ms). The UE (100) can be
configured with different values of dlCOTTimer for different use
cases, for e.g. the UE (100) can be configured with different
dlCOTTimer values for different timers T.
[0108] (2): The UE (100) starts dlCOTTimer based on triggering
criteria defined for each timer and is discussed further in the
disclosure.
[0109] (3): While the dlCOTTimer is running, the UE (100) shall
monitor the downlink channel based on one or more of below
options:
[0110] (a): When the dlCOTTimer is running, the UE (100) monitors
for SSB transmission from the base station (200).
[0111] (b): When the dlCOTTimer is running, the UE (100) monitors
for the SSB transmission from the base station (200) corresponding
to the SSB index associated with the transmitted PRACH.
[0112] (c): When the dlCOTTimer is running, the UE (100) monitors
for any CSI-RS transmission from the base station (200)
corresponding to the serving cell (if CSI-RS resources are
configured to the UE (100) for the serving cell).
[0113] (d): When the dlCOTTimer is running, the UE (100) monitors
for CSI-RS transmission from the base station (200) corresponding
to the CSI-RS index of the serving cell associated with the
transmitted PRACH (if CSI-RS resources are configured to the UE
(100) for the serving cell).
[0114] (e): The UE (100) monitors for a PDCCH identified by a cell
common RNTI value (i.e. a predefined RNTI value or RNTI value
configured by the base station (200) e.g. in system information or
dedicated configuration).
[0115] (f): The UE (100) monitors for a preamble/any transmission
from the base station (200) indicating start/end/ongoing COT for
the given serving cell of the base station.
[0116] (g): The UE (100) monitors for a base station transmission
according to the monitoring criteria defined for timer T. For e.g.
the UE (100) monitors for a PDCCH identified by RA-RNTI
corresponding to the PRACH transmitted by the UE (100) or C-RNTI in
case of beam failure recovery request, the UE (100) monitors for a
PDCCH identified by the C-RNTI for the case when the dlCOTTimer is
initiated for DRX timer, or when dlCOTTimer is initiated in
response to scheduling request transmission, etc.
[0117] (4): On reception of dlCOTActive indication, the UE (100)
stops dlCOTTimer and starts T after L2 duration. L2 can be
different for different MAC timers. Value of L2 can be configurable
via RRC configuration/MAC CE/DCI or can have a pre-defined value as
well.
[0118] (5): One instance of dlCOTTimer can be shared by multiple
timers T. For example, if dlCOTTimer is already running for a timer
T1 (e.g. drx-InactivityTimer), then the UE (100) does not need to
initiate another instance of dlCOTTimer in order to trigger timer
T2 (e.g. drx-RetransmissionTimerUL).
[0119] FIG. 2B is a schematic diagram illustrating a timer handling
in an adaptive procedure, according to the embodiments as disclosed
herein.
[0120] Adaptive Approach: In one embodiment, for any
timer/monitoring window, let's say T, the proposed method
introduces a new timer called dlCOTTimer.
[0121] (1): Duration of dlCOTTimer in terms of slots or symbols or
absolute time units (e.g. in units of ms). The UE (100) can be
configured with different values of the dlCOTTimer for different
use cases, for e.g. the UE (100) can be configured with different
dlCOTTimer values for different timers T.
[0122] (2): The UE (100) starts dlCOTTimer based on triggering
criteria defined for each timer and is discussed in the patent
disclosure.
[0123] (3): While the dlCOTTimer is running, the UE (100) shall
monitor the downlink channel based on one or more of below
options:
[0124] (a): When the dlCOTTimer is running, the UE (100) monitors
for SSB transmission from the base station (200).
[0125] (b): When the dlCOTTimer is running, the UE (100) monitors
for SSB transmission from the base station (200) corresponding to
the SSB index associated with the transmitted PRACH.
[0126] (c): When dlCOTTimer is running, the UE (100) monitors for
any CSI-RS transmission from the base station (200) corresponding
to the serving cell (if the CSI-RS resources are configured to the
UE (100) for the serving cell).
[0127] (d): When the dlCOTTimer is running, the UE (100) monitors
for CSI-RS transmission from the base station (200) corresponding
to the CSI-RS index of the serving cell associated with the
transmitted PRACH (if CSI-RS resources are configured to the UE
(100) for the serving cell).
[0128] (e): The UE (100) monitors for a PDCCH identified by a cell
common RNTI value (i.e. a predefined RNTI value or RNTI value
configured by the base station (200) e.g. in system information or
dedicated configuration).
[0129] (f): The UE (100) monitors for a preamble/any transmission
from the base station (200) indicating start/end/ongoing COT for
the given serving cell of the base station (200).
[0130] (g): The UE (100) monitors for the base station transmission
based on the monitoring criteria defined for timer T. For e.g. the
UE (100) monitors for the PDCCH identified by RA-RNTI corresponding
to the PRACH transmitted by the UE (100) or C-RNTI in case of beam
failure recovery request, the UE (100) monitors for the PDCCH
identified by C-RNTI for the case when dlCOTTimer is initiated for
DRX timer, or when dlCOTTimer is initiated in response to
scheduling request transmission, etc.
[0131] (4): On reception of dlCOTActive indication, if T has not
been started even once, the UE (100) stops dlCOTTimer and starts T
after L2 duration. L2 can be different for different timers. L2 can
be configurable via the RRC configuration/MAC CE/DCI or can have a
static configuration as well.
[0132] (5): On reception of dlCOTActive indication, if T has been
paused/suspended--
[0133] (a): If the dlCOTTimer is running, the UE (100) shall:
[0134] (i): pause/suspend dlCOTTimer and resume T after L3
duration.
[0135] (ii): stop dlCOTTimer and resume T after L3 duration.
[0136] (iii): L3 can be different for different timers. L3 can be
configurable via RRC configuration/MAC CE/DCI or can have a static
configuration as well.
[0137] (6): On reception of dlCOTInactive indication--
[0138] (a): If T is running, the UE (100) shall--
[0139] (i): Pause/suspend T and resume dlCOTTimer after L4
duration.
[0140] (ii): Pause/suspend T and restart dlCOTTimer after L4
duration.
[0141] (iii): L4 can be different for different timers. L4 can be
configurable via RRC configuration/MAC CE/DCI or can have a static
configuration as well.
[0142] (7): One instance of the dlCOTTimer can be shared by
multiple timers T. For example, if the dlCOTTimer is already
running for a timer T1 (e.g. drx-InactivityTimer), then the UE
(100) does not need to initiate another instance of the dlCOTTimer
in order to trigger timer T2 (e.g., drx-RetransmissionTimerUL)
[0143] Configuration of dlCOTTimer: For any timer/monitoring window
T, the associated dlCOTTimer, as mentioned above in
Adaptive/Non-Adaptive Approach, can be configured in following
manner.
[0144] (a): In one embodiment, the dlCOTTimer is provided in common
configuration which is applicable to one or more timers T. For e.g.
the RRC configuration for the dlCOTTimer is provided per serving
cell or per MAC entity or per bandwidth part configured for a cell.
The UE (100) applies same value of dlCOTTimer for all the MAC
timers which are operating within the given serving cell or MAC
entity or bandwidth part, respectively.
[0145] (b): In another embodiment, configuration of dlCOTTimer is
provided for each timer T.
[0146] (i): Independent configuration for dlCOTTimer can be
provided for each configuration of following timers:
ra-ResponseWindow, bfr-ResponseWindow,
ra-ContentionResolutionTimer, drx-onDurationTimer,
drx-InactivityTimer, drx-RetransmissionTimerDL,
drx-RetransmissionTimerUL, drx-ShortCycleTimer,
drx-HARQ-RTT-TimerDL, drx-HARQ-RTT-TimerUL, periodicBSR-Timer,
retxBSR-Timer, sr-ProhibitTimer, phr-PeriodicTimer, and
phr-ProhibitTimer.
[0147] (ii): Independent configuration for dlCOTTimer can be
provided for each of configuration of following procedures:
[0148] (1): All DRX timers share the same value of dlCOTTimer.
[0149] (2): All timers related to random access procedure share
same value of the dlCOTTimer.
[0150] (3): All timers related to a buffer status reporting
procedure share same value of dlCOTTimer.
[0151] (4): All timers related to power headroom reporting
procedure share same value of the dlCOTTimer.
[0152] (5): All timers related to scheduling request procedure
share same value of the dlCOTTimer.
[0153] (c): In another embodiment, the UE shall use value of
dlCOTTimer provided in common configuration if configuration of
dlCOTTimer is not provided for a specific timer T.
[0154] (2): In another embodiment, the configurations corresponding
to various dlCOTTimer can be modified via RRC signaling/MAC CE
based signaling/DCI based signaling.
[0155] Random Access Response Timer Operation:
[0156] (1): The UE (100) can initiate the dlCOTTimer for RAR
reception if one or more of below conditions are true:
[0157] (a): the UE (100) is provided with RRC configuration for
monitoring for base station transmissions containing information
about the acquired COT and configuration of the dlCOTTimer.
[0158] (b): the UE (100) is monitoring for the RAR in an unlicensed
carrier.
[0159] (c): the UE (100) has performed PRACH transmission on an
unlicensed carrier
[0160] (2): The UE (100) starts the dlCOTTimer corresponding to
random access response timer according to the configuration
provided for RAR reception at one of the following instances:
[0161] (a): the UE (100) starts dlCOTTimer after the MAC entity
instructs the physical layer to perform the PRACH transmission.
[0162] (b): The UE (100) starts dlCOTTimer X time units after the
physical layer starts transmission on the first PRACH occasion
(e.g. in case of multiple PRACH transmission occasions). The
physical layer may indicate the start of PRACH transmission to the
MAC layer. Value of X can be configured by the base station (200)
(e.g. using system information or dedicated configuration) or can
be a predefined value (e.g. value of X can be 0).
[0163] (c): The UE (100) starts dlCOTTimer X time units after the
end of PRACH transmission performed by the physical layer (e.g. in
case of multiple PRACH transmission occasions, end of PRACH
transmission corresponds to the last PRACH transmission occasion).
The physical layer may indicate the end of PRACH transmission to
the MAC layer. Value of X can be configured by the base station
(200) (e.g. using system information or dedicated configuration) or
can be a predefined value (e.g. value of X can be 0).
[0164] (3): The UE (100) suspends/stops/resumes/starts dlCOTTimer
and ra-ResponseWindow according to procedure mentioned in
"Non-Adaptive Approach" or "Adaptive Approach"
[0165] (4): The UE (100) shall monitor the PDCCH for downlink
assignment when ra-ResponseWindow is running:
[0166] (a): In an embodiment, the UE (100) monitors for only PDCCH
identified by the RA-RNTI or the C-RNTI in case of beam failure
recovery request, when ra-ResponseWindow is running.
[0167] (b): In another embodiment, the UE (100) monitors for both
PDCCH identified by the RA-RNTI or the C-RNTI in case of beam
failure recovery request and base station indication containing
information about the COT (according to the configuration indicated
in point 1)
[0168] (5): On successful reception of a RAR addressed to the UE
(100), the UE shall stop dlCOTTimer (if running) and
ra-ResponseWindow
[0169] (6): On expiry of dlCOTTimer the UE (100) initiates
RAR-LBT-FAILURE procedure:
[0170] (7): On ra-ResponseWindow expiry, the UE (100) shall perform
procedure as on Random Access Response Failure.
[0171] Contention Resolution Timer Operation:
[0172] (1): The UE (100) can initiate dlCOTTimer for Message-4
reception if one or more of below conditions are true:
[0173] (a): The UE (100) is provided with the RRC configuration for
monitoring for the base station transmissions containing
information about the acquired COT and configuration of
dlCOTTimer.
[0174] (b): the UE (100) is monitoring for Message-4 on an
unlicensed carrier.
[0175] (c): the UE (100) has performed the PRACH transmission on
the unlicensed carrier.
[0176] (d): the UE (100) has performed Message-3 transmission on
the unlicensed carrier.
[0177] (2): The UE (100) starts dlCOTTimer corresponding to
contention resolution timer according to the configuration provided
at one of the following instances:
[0178] (a): the UE (100) starts the dlCOTTimer after MAC entity
instructs physical layer to perform Message-3 transmission.
[0179] (b): the UE (100) starts dlCOTTimer X time units after
physical layer starts transmission on the first symbol/slot of
Message-3 (or Message-4) (e.g. in case of uplink grant for
Message-3 may contains multiple symbols/slots). The physical layer
may indicate the start of Message-3 transmission to the MAC layer.
The value of X can be indicated by the base station (200) (e.g.
using system information or dedicated configuration or DCI or MAC
CE) or can be a predefined value (e.g. value of X can be 0).
[0180] (c): the UE (100) starts dlCOTTimer X time units after the
end of Message-3 transmission performed by the physical layer (e.g.
in case of message-3 grant includes multiple symbols/slots, end of
the message-3 transmission corresponds to the last symbol/slot of
the message-3 transmission). The physical layer may indicate the
end of the message-3 transmission to the MAC layer. Value of X can
be indicated by the base station (200) (e.g. using system
information or dedicated configuration or DCI or MAC CE) or can be
a predefined value (e.g. value of X can be 0).
[0181] (3): the UE (100) suspends/stops/resumes/starts dlCOTTimer
and ra-ContentionResolutionTimer according to procedure mentioned
in "Non-Adaptive Approach" or "Adaptive Approach"
[0182] (4): The UE (100) shall monitor the PDCCH for downlink
assignment when ra-ContentionResolutionTimer is running:
[0183] (a): In an embodiment, the UE (100) monitors for only PDCCH
identified by the TC-RNTI or C-RNTI in case C-RNTI MAC CE was
included within Message-3, when ra-ContentionResolutionTimer is
running.
[0184] (b): In another embodiment, the UE (100) monitors for both
PDCCH identified by the TC-RNTI or the C-RNTI in case C-RNTI MAC CE
was included within Message-3 and base station indication
containing information about the COT.
[0185] (5): On successful reception of Message-4 transmission
addressed to the UE (100), the UE (100) shall stop dlCOTTimer (if
running) and ra-ContentionResolutionTimer.
[0186] (6): On expiry of dlCOTTimer, the UE (100) initiates
CR-LBT-FAILURE procedure
[0187] (7): On ra-ContentionResolutionTimer expiry, the UE (100)
shall perform procedure as on Contention Resolution Failure.
[0188] (8): If ra-ContentionResolutionTimer is running and the UE
(100) receives dlCOTInactive indication, then the UE (100) stops
ra-ContentionResolutionTimer
[0189] sr-Prohibit Timer Operation:
[0190] (1): the UE (100) can initiate dlCOTTimer if one or more of
below conditions are true:
[0191] (a): the UE (100) is provided with RRC configuration for
monitoring for base station transmissions containing information
about the acquired COT and configuration of dlCOTTimer
[0192] (b): the UE (100) is monitoring for the PDCCH or the PDSCH
transmission on the unlicensed carrier
[0193] (c): the UE (100) has performed scheduling request (SR)
transmission on the unlicensed carrier
[0194] (2): UE (100) starts dlCOTTimer corresponding to
sr-ProhibitTimer according to the configuration provided at one of
the following instances:
[0195] (a): the UE (100) starts dlCOTTimer after the MAC entity
instructs the physical layer to perform scheduling request
transmission.
[0196] (b): the UE (100) starts dlCOTTimer X time units after
physical layer starts transmission on the first scheduling request
occasion (e.g. in case of multiple scheduling request transmission
occasions). The physical layer may indicate the start of scheduling
request transmission to the MAC layer. Value of X can be configured
by the base station (200) (e.g. using system information or
dedicated configuration) or can be a predefined value (e.g. value
of X can be 0).
[0197] (c): the UE (100) starts dlCOTTimer X time units after the
end of scheduling request transmission performed by the physical
layer (e.g. in case of multiple scheduling request transmission
occasions, end of scheduling request transmission corresponds to
the last scheduling request transmission occasion). The physical
layer may indicate the end of scheduling request transmission to
the MAC layer. Value of X can be configured by the base station
(200) (e.g. using system information or dedicated configuration) or
can be a predefined value (e.g. value of X can be 0).
[0198] (3): The UE (100) suspends/stops/resumes/starts dlCOTTimer
and sr-ProhibitTimer according to procedure mentioned in
"Non-Adaptive Approach" or "Adaptive Approach"
[0199] (4): On the dlCOTTimer expiry, the UE (100) shall perform
SR-LBT-FAILURE procedure.
[0200] (5): The UE (100) shall not perform transmission of a
scheduling request while the dlCOTTimer is running.
[0201] periodicBSR-Timer Operation:
[0202] (1): If the Buffer Status reporting procedure determines
that at least one BSR has been triggered and not cancelled and if
UL-SCH resources are available for a new immediate transmission
then, the UE (100) shall start dlCOTTimer corresponding to
periodicBSR-Timer.
[0203] (2): The UE (100) suspends/stops/resumes/starts the
dlCOTTimer and periodicBSR-Timer according to procedure mentioned
in "Non-Adaptive Approach" or "Adaptive Approach"
[0204] (3): On periodicBSR-Timer expiry a periodic BSR shall be
triggered.
[0205] (4): On the dlCOTTimer expiry, the UE (100) shall perform
PERIODIC-BSR-LBT-FAILURE procedure.
[0206] retxBSR-Timer Operation:
[0207] (1): If the buffer status reporting procedure determines
that at least one BSR has been triggered and not cancelled and if
UL-SCH resources are available for a new immediate transmission, or
upon reception of a grant for transmission of new data on any
UL-SCH, the UE (100) shall start the dlCOTTimer corresponding to
retxBSR-Timer.
[0208] (2): the UE (100) suspends/stops/resumes/starts the
dlCOTTimer and the retxBSR-Timer according to procedure mentioned
in "Non-Adaptive Approach" or "Adaptive Approach
[0209] (3): On retxBSR-Timer expiry a regular BSR shall be
triggered.
[0210] (4): On the dlCOTTimer expiry, the UE (100) shall perform
RETX-BSR-LBT-FAILURE procedure.
[0211] drx-onDurationTimer Operation:
[0212] (1): The UE (100) can initiate the dlCOTTimer for
drx-onDurationTimer operation if one or more of below conditions
are true:
[0213] (a): the UE (100) is provided with the RRC configuration for
monitoring for base station transmissions containing information
about the acquired COT and configuration of the dlCOTTimer.
[0214] (b): the UE (100) is monitoring for the PDCCH on the
unlicensed carrier.
[0215] (2): The UE (100) starts the dlCOTTimer corresponding to
drx-onDurationTimer according to the configuration provided at one
or more of the following instances:
[0216] (a): The UE (100) starts the dlCOTTimer X time units after
SFN and subframe where
[0217] (i): If the Short DRX Cycle is used, and
[(SFN.times.10)+subframe number] modulo
(drx-ShortCycle)=(drx-StartOffset) modulo (drx-ShortCycle) or
[0218] (ii): If the Long DRX Cycle is used, and
[(SFN.times.10)+subframe number] modulo
(drx-LongCycle)=drx-StartOffset.
[0219] (iii): Value of X can be indicated by the base station (200)
(e.g. using system information or dedicated configuration or the
DCI or the MAC CE) or can be a predefined value (e.g. value of X
can be 0).
[0220] (b): The UE (100) starts the dlCOTTimer X time units after
start of a pre-configured time window, where the time window
configuration includes at least time offset of start occasion of
time window, time periodicity of time window. For instance, the
time window can be discrete monitoring timing configuration
provided to the UE (100), or the time window can be any
configuration provided to the UE (100) using dedicated
configuration. The value of X can be indicated by the base station
(200) (e.g. using system information or dedicated configuration or
DCI or MAC CE) or can be a predefined value (e.g. value of X can be
0).
[0221] (3): The UE (100) suspends/stops/resumes/starts the
dlCOTTimer and drx-onDurationTimer according to procedure mentioned
in "Non-Adaptive Approach" or "Adaptive Approach"
[0222] (4): The UE (100) shall monitor the PDCCH for downlink
assignment when the drx-OnDurationTimer is running:
[0223] (a): In an embodiment, the UE (10) monitors for only PDCCH
identified by the C-RNTI.
[0224] (b): In another embodiment, the UE (100) monitors for both
PDCCH identified by the C-RNTI and base station indication
containing information about COT.
[0225] (5): On successful reception of a DRX command MAC CE or a
Long DRX Command MAC CE, the UE (100) shall stop dlCOTTimer (if
running) and drx-OnDurationTimer.
[0226] (6): On expiry of dlCOTTimer, the UE (100) initiates
ON-DRX-LBT-FAILURE procedure.
[0227] (7): On expiry or stoppage of drx-onDurationTimer, the UE
(100) stops the dlCOTTimer if running
[0228] (8): If drx-OnDurationTimer is running and the UE (100)
receives dlCOTInactive indication, then the UE (100) stops
drx-OnDurationTimer.
[0229] drx-InactivityTimer Operation:
[0230] (1): The UE (100) can initiate dlCOTTimer for
drx-InactivityTimer operation if one or more of below conditions
are true:
[0231] (a): The UE (100) is provided with the RRC configuration for
monitoring for base station transmissions containing information
about the acquired COT and configuration of dlCOTTimer.
[0232] (b): The UE (100) is monitoring for PDCCH on the unlicensed
carrier
[0233] (2): The UE (100) starts dlCOTTimer X time units after the
UE (100) receives a PDCCH indicating a new transmission (DL or UL).
The value of X can be configured by the base station (200) (e.g.
using system information or dedicated configuration) or can be a
predefined value (e.g. value of X can be 0).
[0234] (3): The UE (100) suspends/stops/resumes/starts dlCOTTimer
and drx-InactivityTimer according to procedure mentioned in
"Non-Adaptive Approach" or "Adaptive Approach"
[0235] (4): The UE (100) shall monitor the PDCCH for downlink
assignment when drx-InactivityTimer is running:
[0236] (a): In an embodiment, the UE (100) monitors for only PDCCH
identified by the C-RNTI.
[0237] (b): In another embodiment, the UE (100) monitors for both
PDCCH identified by the C-RNTI and base station indication
containing information about the COT.
[0238] (5): On successful reception of the DRX command MAC CE or a
Long DRX Command MAC CE, the UE (100) shall stop dlCOTTimer (if
running) and drx-InactivityTimer.
[0239] (6): On expiry of the dlCOTTimer, the UE (100) initiates
IN-DRX-LBT-FAILURE procedure.
[0240] (7): On expiry or stoppage of drx-InactivityTimer, the UE
(100) stops the dlCOTTimer if running
[0241] (8): If drx-InactivityTimer is running and the UE (100)
receives the dlCOTInactive indication, then the UE (100) stops
drx-InactivityTimer.
[0242] drx-RetransmissionTimerUL Operation:
[0243] (1): The UE (100) can initiate dlCOTTimer for
drx-RetransmissionTimerUL operation if one or more of below
conditions are true:
[0244] (a): The UE (100) is provided with the RRC configuration for
monitoring for base station transmissions containing information
about the acquired COT and configuration of dlCOTTimer.
[0245] (b): The UE (100) is monitoring for PDCCH on the unlicensed
carrier.
[0246] (2): The UE (100) starts dlCOTTimer X time units after
drx-HARQ-RTT-TimerUL expires. The value of X can be configured by
the base station (200) (e.g. using system information or dedicated
configuration) or can be a predefined value (e.g. value of X can be
0).
[0247] (3): The UE (100) suspends/stops/resumes/starts the
dlCOTTimer and drx-RetransmissionTimerUL according to procedure
mentioned in "Non-Adaptive Approach" or "Adaptive Approach"
[0248] (4): The UE (100) shall monitor the PDCCH for downlink
assignment when the drx-RetransmissionTimerUL is running:
[0249] (a): In an embodiment, the UE (100) monitors for only PDCCH
identified by the C-RNTI.
[0250] (b): In another embodiment, the UE (100) monitors for both
PDCCH identified by the C-RNTI and the base station indication
containing information about the COT.
[0251] (5): On successful reception of the PDCCH indicating the UL
transmission or if the MAC PDU is transmitted in a configured
uplink grant, the UE (100) shall stop the dlCOTTimer (if running)
and drx-RetransmissionTimerUL for the HARQ process corresponding to
the UL transmission.
[0252] (6): On expiry of the dlCOTTimer, the UE (100) initiates
RETU-DRX-LBT-FAILURE procedure.
[0253] (7): On expiry or stoppage of drx-RetransmissionTimerUL, the
UE (100) stops dlCOTTimer if running for the corresponding HARQ
process.
[0254] (8): If drx-RetransmissionTimerUL is running and the UE
(100) receives dlCOTInactive indication, then the UE (100) stops
drx-RetransmissionTimerUL for the corresponding HARQ process.
[0255] drx-RetransmissionTimerDL Operation:
[0256] (1): The UE (100) can initiate dlCOTTimer for
drx-RetransmissionTimerDL operation if one or more of below
conditions are true:
[0257] (a): The UE (100) is provided with the RRC configuration for
monitoring for base station transmissions containing information
about the acquired COT and configuration of dlCOTTimer.
[0258] (b): The UE (100) is monitoring for the PDCCH on the
unlicensed carrier.
[0259] (2): The UE (100) starts dlCOTTimer X time units after
drx-HARQ-RTT-TimerDL expires and if the data of the corresponding
HARQ process was not successfully decoded. The value of X can be
configured by the base station (200) (e.g. using system information
or dedicated configuration) or can be a predefined value (e.g.
value of X can be 0).
[0260] (3): The UE (100) suspends/stops/resumes/starts the
dlCOTTimer and drx-RetransmissionTimerDL according to procedure
mentioned in "Non-Adaptive Approach" or "Adaptive Approach"
[0261] (4): The UE (100) monitors the PDCCH for downlink assignment
when drx-RetransmissionTimerDL is running:
[0262] (a): In an embodiment, the UE (100) monitors for only PDCCH
identified by the C-RNTI.
[0263] (b): In another embodiment, the UE (100) monitors for both
PDCCH identified by the C-RNTI and base station indication
containing information about COT.
[0264] (5): On successful reception of the PDCCH indicating the DL
transmission or if the DL assignment has been configured, the UE
(100) shall stop dlCOTTimer (if running) and
drx-RetransmissionTimerDL for the HARQ process corresponding to the
DL transmission.
[0265] (6): On expiry of the dlCOTTimer, the UE (100) initiates
RETD-DRX-LBT-FAILURE procedure
[0266] (7): On expiry or stoppage of drx-RetransmissionTimerDL, the
UE (100) stops dlCOTTimer if running for the corresponding HARQ
process.
[0267] (8): If drx-RetransmissionTimerDL is running and the UE
(100) receives dlCOTInactive indication then, the UE (100) stops
drx-RetransmissionTimerDL for the corresponding HARQ process.
[0268] FIG. 2C is a schematic diagram illustrating a network
indication based timer restart, according to the embodiments as
disclosed herein
[0269] Base station Indication based Timer restart:
[0270] (1): If the base station (200) is able to acquire the
channel using a short LBT, but is unsuccessful to acquire the
channel using a long LBT, then the base station (200) acquires the
channel using the short LBT and the base station (200) transmits
the indication to the UE(s) (100) indicating failure to acquire
channel using the long LBT. The indication from the base station
(200) can be a common broadcast signal or message which can be
received by all the UEs (100) listening to the base station
transmissions or can be a UE specific message which can be received
by the UE(s) (100). In an embodiment, the indication can be a
signal which is reserved to provide negative indication of long LBT
unsuccessful e.g. SSB transmission with a predefined or configured
physical cell identity or a DeModulation Reference Signal (DM-RS)
signal or CSI-RS transmission. In another embodiment, the
indication can be in form of explicit parameter value contained
within a master information block or the system information block
or common DCI.
[0271] (2): The base station (200) sends the indication mentioned
above--
[0272] (a): In an embodiment, differently for every (or few) timers
separately using on same or different modes on indication.
[0273] (b): In another embodiment, one indication for restart of
all timers.
[0274] (c): In another embodiment, one indication to trigger
restart of timers as per their configuration (e.g. Number of
indications required for restart). This configuration can be
static/semi-static/configurable via the RRC message/configurable
via the MAC CE.
[0275] (3): For any timer/window T, on receiving the base station
indication of unable to acquire channel using long LBT, the UE
(100) restarts timer T (if running)
[0276] Random Access Response Timer Operation:
[0277] (1): The UE (100) starts ra-ResponseWindow according to the
configuration provided for the RAR reception at one of the
following instances:
[0278] (a): The UE (100) starts ra-ResponseWindow after MAC entity
instructs the physical layer to perform the PRACH transmission.
[0279] (b): The UE (100) starts ra-ResponseWindow X time units
after the physical layer starts transmission on the first PRACH
occasion (e.g. in case of multiple PRACH transmission occasions).
The physical layer may indicate the start of PRACH transmission to
the MAC layer. Value of X can be configured by the base station
(200) (e.g. using system information or dedicated configuration) or
can be a predefined value (e.g. value of X can be 0).
[0280] (c): The UE (100) starts ra-ResponseWindow X time units
after the end of PRACH transmission performed by the physical layer
(e.g. in case of multiple PRACH transmission occasions, end of
PRACH transmission corresponds to the last PRACH transmission
occasion). The physical layer may indicate the end of PRACH
transmission to the MAC layer. Value of X can be configured by the
base station (200) (e.g. using system information or dedicated
configuration) or can be a predefined value (e.g. value of X can be
0).
[0281] (d): The UE (100) can be configured with the RAR timing
window (contains parameters time offset with respect to {SFN=0,
subframe/slot=0} where timing window is started, timing window
periodicity and duration of each timing window occurrence) at the
beginning of which the UE (100) can initiate ra-ResponseWindow. X
time units after transmission of PRACH, the UE (100) initiates
ra-ResponseWindow at the first opportunity where the given RAR
timing window starts. Value of X can be configured by the base
station (200) (e.g. using system information or dedicated
configuration) or can be a predefined value (e.g. value of X can be
0).
[0282] (2): While the ra-ResponseWindow is running, the UE (100)
shall monitor the downlink channel based on one or more of below
options:
[0283] (a): In an embodiment, when ra-ResponseWindow is running,
the UE (100) monitors for the SSB transmission from the base
station (200). In further extension, the UE (100) does not need to
monitor for the SSB transmissions from the base station (200) when
COT is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) where the
UE (100) has performed PRACH.
[0284] (b): In another embodiment, when the ra-ResponseWindow is
running, the UE (100) monitors for the SSB transmission from the
base station (200) corresponding to the SSB index associated with
the transmitted PRACH. In further extension, the UE (100) does not
need to monitor for the SSB transmissions from the base station
(200) when the COT is ongoing (e.g. based on dlCOTActive and
dlCOTInactive indications) for the given cell of the base station
(200) where the UE (100) has performed PRACH.
[0285] (c): In another embodiment, when ra-ResponseWindow is
running, the UE (100) monitors for any CSI-RS transmission from the
base station (200) corresponding to the serving cell (if CSI-RS
resources are configured to the UE (100) for the serving cell). In
further extension of this solution, the UE (100) does not need to
monitor for CSI-RS transmissions from the base station (200) when
the COT is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) where the
UE (100) has performed PRACH.
[0286] (d): In another embodiment, when ra-ResponseWindow is
running, the UE (100) monitors for CSI-RS transmission from the
base station (200) corresponding to the CSI-RS index of the serving
cell associated with the transmitted PRACH (if CSI-RS resources are
configured to the UE (100) for the serving cell). In further
extension of this solution, the UE (100) does not need to monitor
for CSI-RS transmissions from the base station (200) when COT is
ongoing (e.g. based on dlCOTActive and dlCOTInactive indications)
for the given cell of the base station (200) where the UE (100) has
performed PRACH.
[0287] (e): In another embodiment, the UE (100) monitors for the
PDCCH identified by the cell common RNTI value (i.e. a predefined
RNTI value or the RNTI value configured by the base station (200)
e.g. in system information or dedicated configuration). In further
extension of this solution, the UE (100) does not need to monitor
for the PDCCH transmissions addressed to the cell common RNTI from
the base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) where the UE (100) has performed PRACH.
[0288] (f): In another embodiment, the UE (100) monitors for a
preamble/any transmission from the base station (200) indicating
start/end/ongoing COT for the given serving cell of the base
station (200). In further extension of this solution, the UE (100)
does not need to monitor for preamble/any transmissions from the
base station (200) indicating start/end/ongoing COT, when the COT
is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) where the
UE (100) has performed PRACH.
[0289] (g): In another embodiment, the UE (100) monitors for a
PDCCH identified by the RA-RNTI corresponding to the PRACH
transmitted by the UE (100) or C-RNTI in case of beam failure
recovery request.
[0290] (3): On successfully transmitting RACH preamble, the UE
(100) initializes a counter RACH-LBT-FAILURE=0
[0291] (4): On receiving the base station indication of unable to
acquire channel using the long LBT, the UE (100) restarts the
ra-ResponseWindow (if running) and increments RACH-LBT-FAILURE by
1.
[0292] (5): If RACH-LBT-FAILURE>MAX-RACH-LBT-FAILURE (the value
can be configured by RRC), then the UE (100) performs the
RAR-LBT-FAILURE procedure.
[0293] (6): On successful reception of RAR addressed to the UE
(100), the UE (100) shall stop ra-ResponseWindow and consider this
Random Access Response reception successful.
[0294] (7): On ra-ResponseWindow expiry, the UE (100) shall perform
procedure as on Random Access Response Failure.
[0295] Contention Resolution Timer Operation:
[0296] (1): The UE (100) starts ra-ContentionWindowTimer according
to the configuration provided for RAR reception at one of the
following instances:
[0297] (a): the UE (100) starts ra-ContentionWindowTimer after MAC
entity instructs physical layer to perform the Message-3
transmission.
[0298] (b): The UE (100) starts ra-ContentionWindowTimer X time
units after the physical layer starts transmission on the first
symbol/slot of Message-4 (e.g. in case of uplink grant for
Message-3 may contains multiple symbols/slots). The physical layer
may indicate the start of Message-3 transmission to the MAC layer.
Value of X can be indicated by the base station (200) (e.g. using
system information or dedicated configuration or DCI or MAC CE) or
can be a predefined value (e.g. value of X can be 0).
[0299] (c): The UE (100) starts ra-ContentionWindowTimer X time
units after the end of Message-3 transmission performed by physical
layer (e.g. in case of Message-3 grant includes multiple
symbols/slots, end of Message-3 transmission corresponds to the
last symbol/slot of Message-3 transmission). The physical layer may
indicate the end of message-3 transmission to the MAC layer. The
value of X can be indicated by the base station (200) (e.g. using
system information or dedicated configuration or the DCI or the MAC
CE) or can be a predefined value (e.g. value of X can be 0).
[0300] (d): The UE (100) can be configured with the CR timing
window (contains parameters time offset with respect to {SFN=0,
subframe/slot=0} where the timing window is started, timing window
periodicity and duration of each timing window occurrence) at the
beginning of which the UE (100) can initiate
ra-ContentionResolutionTimer. X time units after transmission of
PRACH, the UE (100) initiates ra-ContentionResolutionTimer at the
first opportunity where the given RAR timing window starts. Value
of X can be indicated by the base station (200) (e.g. using system
information or dedicated configuration or DCI or MAC CE) or can be
a predefined value (e.g. value of X can be 0).
[0301] (2): While the ra-ContentionWindowTimer is running, the UE
(100) shall monitor the downlink channel based on one or more of
below options:
[0302] (a): In an embodiment, when ra-ContentionWindowTimer is
running, the UE (100) monitors for the SSB transmission from the
base station (200). In further extension of this solution, the UE
(100) does not need to monitor for SSB transmissions from the base
station (200) when the COT is ongoing (e.g. based on dlCOTActive
and dlCOTInactive indications) for the given cell of the base
station (200) where the UE (100) has performed PRACH.
[0303] (b): In another embodiment, when ra-ContentionWindowTimer is
running, the UE (100) monitors for the SSB transmission from the
base station (200) corresponding to the SSB index associated with
the transmitted PRACH. In further extension of this solution, the
UE (100) does not need to monitor for the SSB transmissions from
the base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) where the UE (100) has performed PRACH.
[0304] (c): In another embodiment, when ra-ContentionWindowTimer is
running, the UE (100) monitors for any CSI-RS transmission from the
base station (200) corresponding to the serving cell (if CSI-RS
resources are configured to the UE (100) for the serving cell). In
further extension of this solution, the UE (100) does not need to
monitor for CSI-RS transmissions from the base station (200) when
the COT is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) where the
UE (100) has performed PRACH.
[0305] (d): In another embodiment, when ra-ContentionWindowTimer is
running, the UE (100) monitors for CSI-RS transmission from the
base station (200) corresponding to the CSI-RS index of the serving
cell associated with the transmitted PRACH (if CSI-RS resources are
configured to the UE (100) for the serving cell). In further
extension of this solution, the UE (100) does not need to monitor
for CSI-RS transmissions from the base station (200) when the COT
is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) where the
UE (100) has performed PRACH.
[0306] (e): In another embodiment, the UE (100) monitors for a
PDCCH identified by a cell common RNTI value (i.e. a predefined
RNTI value or RNTI value configured by the base station (200) e.g.
in system information or dedicated configuration). In further
extension of this solution, the UE (100) does not need to monitor
for the PDCCH transmissions addressed to the cell common RNTI from
the base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) where the UE (100) has performed PRACH.
[0307] (f): In another embodiment, the UE (100) monitors for a
preamble/any transmission from the base station (200) indicating
start/end/ongoing COT for the given serving cell of the base
station (200). In further extension of this solution, the UE (100)
does not need to monitor for preamble/any transmissions from the
base station (200) indicating start/end/ongoing COT, when the COT
is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) where the
UE (100) has performed PRACH.
[0308] (g): In another embodiment, the UE (100) monitors for PDCCH
identified by TC-RNTI or C-RNTI in case C-RNTI MAC CE was included
within Message-3.
[0309] (3): On successfully transmitting Message-3, the UE (100)
initializes a counter RACH-LBT-FAILURE=0
[0310] (4): On receiving the base station indication of unable to
acquire channel using long LBT, the UE (100) restarts the
ra-ContentionResolutionWindow (if running) and increments
RACH-LBT-FAILURE by 1.
[0311] (5): If RACH-LBT-FAILURE>MAX-RACH-LBT-FAILURE (the value
can be configured by RRC), then the UE (100) performs the
CR-LBT-FAILURE procedure.
[0312] (6): On successful reception of Message-4 transmission
addressed to the UE (100), the UE (100) shall stop
ra-ContentionResolutionTimer.
[0313] (7): On ra-ContentionResolutionTimer expiry, the UE (100)
shall perform procedure as on Contention Resolution Failure.
[0314] sr-Prohibit Timer Operation:
[0315] (1): On receiving indication of successful transmission of
SR by the lower layers, the UE (100) shall start sr-ProhibitTimer
and initialize SR-LBT-FAILURE-COUNT=0.
[0316] (2): On receiving the base station indication of unable to
acquire channel, the UE (100) will restart sr-ProhibitTimer and
increments SR-LBT-FAILURE-COUNT by 1.
[0317] (3): If SR-LBT-FAILURE-COUNT>SR-LBT-FAILURE-COUNT-MAX
(the value can be configured by RRC), then the UE (100) performs
SR-LBT-FAILURE procedure.
[0318] periodicBSR-Timer Operation:
[0319] (1): If the Buffer Status reporting procedure determines
that at least one BSR has been triggered and not cancelled and if
UL-SCH resources are available for a new immediate transmission
then the UE (100) shall start, periodicBSR-Timer.
[0320] (2): On receiving the base station indication of unable to
acquire channel, the UE (100) will restart periodicBSR-Timer and
increments PERIODIC-BSR-LBT-FAILURE-COUNT by 1.
[0321] (3): If
PERIODIC-BSR-LBT-FAILURE-COUNT>PERIODIC-BSR-LBT-FAILURE-COUNT-MAX
(the value can be configured by RRC), then the UE (100) performs
PERIODIC-BSR-LBT-FAILURE procedure.
[0322] retxBSR-Timer Operation:
[0323] (1): If the Buffer Status reporting procedure determines
that at least one BSR has been triggered and not cancelled and if
UL-SCH resources are available for a new immediate transmission, or
upon reception of a grant for transmission of new data on any
UL-SCH, the UE (100) shall start, retxBSR.
[0324] (2): On receiving the base station indication of unable to
acquire channel, the UE (100) will restart retxBSR-Timer and
increments RETX-BSR-LBT-FAILURE-COUNT by 1.
[0325] (i): If
RETX-BSR-LBT-FAILURE-COUNT>RETX-BSR-LBT-FAILURE-COUNT-MAX (the
value can be configured by RRC), then the UE (100) performs
RETX-BSR-LBT-FAILURE procedure.
[0326] drx-OnDurationTimer Operation:
[0327] (1): The UE (100) starts drx-OnDurationTimer according to
the configuration provided for DRX operation at one of the
following instances:
[0328] (a): The UE (100) starts drx-OnDurationTimer X time units
after SFN and subframe where
[0329] (i): If the Short DRX Cycle is used, and
[(SFN.times.10)+subframe number] modulo
(drx-ShortCycle)=(drx-StartOffset) modulo (drx-ShortCycle) or
[0330] (ii): If the Long DRX Cycle is used, and
[(SFN.times.10)+subframe number] modulo
(drx-LongCycle)=drx-StartOffset.
[0331] (iii): Value of X can be indicated by the base station (200)
(e.g. using system information or dedicated configuration or DCI or
MAC CE) or can be a predefined value (e.g. value of X can be
0).
[0332] (b): The UE (100) starts drx-OnDurationTimer X time units
after start of a pre-configured time window, where the time window
configuration includes at least time offset of start occasion of
time window, time periodicity of time window. For instance, the
time window can be Discrete Monitoring Timing Configuration
provided to the UE (100), or the time window can be any
configuration provided to the UE (100) using dedicated
configuration. The value of X can be indicated by the base station
(200) (e.g. using system information or dedicated configuration or
DCI or MAC CE) or can be a predefined value (e.g. value of X can be
0).
[0333] (2): While the drx-OnDurationTimer is running, the UE (100)
shall monitor the downlink channel based on one or more of below
options:
[0334] (a): In an embodiment, when drx-OnDurationTimer is running,
the UE (100) monitors for SSB transmission from the base station
(200). In further extension of this solution, the UE (100) does not
need to monitor for the SSB transmissions from the base station
(200) when COT is ongoing (e.g. based on dlCOTActive and
dlCOTInactive indications) for the given cell of the base station
(200) for which DRX is configured.
[0335] (b): In another embodiment, when the drx-OnDurationTimer is
running, the UE (100) monitors for any CSI-RS transmission from the
base station (200) corresponding to the serving cell (if CSI-RS
resources are configured to the UE (100) for the serving cell). In
further extension of this solution, the UE (100) does not need to
monitor for the CSI-RS transmissions from the base station (200)
when the COT is ongoing (e.g. based on dlCOTActive and
dlCOTInactive indications) for the given cell of the base station
(200) for which DRX is configured.
[0336] (c): In another embodiment, the UE (100) monitors for a
PDCCH identified by a cell common RNTI value (i.e. a predefined
RNTI value or RNTI value configured by the base station (200) e.g.
in system information or dedicated configuration). In further
extension of this solution, the UE (100) does not need to monitor
for the PDCCH transmissions addressed to cell common RNTI from the
base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) for which DRX is configured.
[0337] (d): In another embodiment, the UE (100) monitors for a
preamble/any transmission from the base station (200) indicating
start/end/ongoing COT for the given serving cell of the base
station (200). In further extension of this solution, the UE (100)
does not need to monitor for preamble/any transmissions from the
base station (200) indicating start/end/ongoing COT, when the COT
is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) for DRX
is configured.
[0338] (e): In another embodiment, the UE (100) monitors for a
PDCCH identified by MAC entity's C-RNTI, CS-RNTI, TPC-PUCCH-RNTI,
TPC-PUSCH-RNTI, and TPC-SRS-RNTI.
[0339] (3): After drx-onDurationTimer is started, the UE (100)
initializes a counter ON-DRX-LBT-COUNTER=0
[0340] (4): On receiving the base station indication of unable to
acquire channel using long LBT, the UE (100) restarts the
drx-OnDurationTimer (if running) and increments ON-DRX-LBT-COUNTER
by 1.
[0341] (5): If ON-DRX-LBT-COUNTER>MAX-ON-DRX-LBT-COUNTER (the
value can be configured by RRC), then the UE (100) performs the
ON-DRX-LBT-FAILURE procedure.
[0342] (6): On successful reception of a PDCCH addressed to C-RNTI
of the UE (100), the UE (100) shall stop drx-OnDurationTimer.
[0343] drx-InactivityTimer Operation:
[0344] (1): The UE (100) starts drx-Inactivity Timer X time units
after UE receives the PDCCH indicating a new transmission (DL or
UL). Value of X can be configured by the base station (200) (e.g.
using system information or dedicated configuration) or can be a
predefined value (e.g. value of X can be 0).
[0345] (2): While the drx-InactivityTimer is running, the UE (100)
shall monitor the downlink channel based on one or more of below
options:
[0346] (a): In an embodiment, when the drx-InactivityTimer is
running, the UE (100) monitors for the SSB transmission from the
base station (200). In further extension of this solution, the UE
(100) does not need to monitor for SSB transmissions from the base
station (200) when the COT is ongoing (e.g. based on dlCOTActive
and dlCOTInactive indications) for the given cell of the base
station (200) for which DRX is configured.
[0347] (b): In another embodiment, when the drx-InactivityTimer is
running, the UE (100) monitors for any CSI-RS transmission from the
base station (200) corresponding to the serving cell (if CSI-RS
resources are configured to the UE (100) for the serving cell). In
further extension of this solution, the UE (100) does not need to
monitor for CSI-RS transmissions from the base station (200) when
the COT is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) for which
DRX is configured.
[0348] (c): In another embodiment, the UE (100) monitors for the
PDCCH identified by the cell common RNTI value (i.e. a predefined
RNTI value or the RNTI value configured by the base station (200)
e.g. in system information or dedicated configuration). In further
extension of this solution, the UE (100) does not need to monitor
for PDCCH transmissions addressed to cell common RNTI from the base
station (200) when the COT is ongoing (e.g. based on dlCOTActive
and dlCOTInactive indications) for the given cell of the base
station (200) for which DRX is configured.
[0349] (d): In another embodiment, the UE (100) monitors for a
preamble/any transmission from the base station (200) indicating
start/end/ongoing COT for the given serving cell of the base
station (200). In further extension of this solution, the UE (100)
does not need to monitor for preamble/any transmissions from the
base station (200) indicating start/end/ongoing COT, when the COT
is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) for DRX
is configured.
[0350] (e): In another embodiment, the UE (100) monitors for the
PDCCH identified by MAC entity's C-RNTI, CS-RNTI, TPC-PUCCH-RNTI,
TPC-PUSCH-RNTI, and TPC-SRS-RNTI.
[0351] (3): After drx-InactivityTimer is started, the UE (100)
initializes the counter IN-DRX-LBT-COUNTER=0
[0352] (4): On receiving the base station indication of unable to
acquire channel using the long LBT, the UE (100) restarts the
drx-InactivityTimer (if running) and increments IN-DRX-LBT-COUNTER
by 1.
[0353] (5): If IN-DRX-LBT-COUNTER>MAX-IN-DRX-LBT-COUNTER (the
value can be configured by RRC), then the UE (100) performs the
IN-DRX-LBT-FAILURE procedure.
[0354] (6): On successful reception of the DRX Command MAC CE or a
Long DRX Command MAC CE, the UE (100) shall stop
drx-InactivityTimer.
[0355] drx-RetransmissionTimerUL Operation:
[0356] (1): The UE (100) starts drx-RetransmissionTimerUL X time
units after drx-HARQ-RTT-TimerUL expires. The value of X can be
configured by the base station (200) (e.g. using system information
or dedicated configuration) or can be a predefined value (e.g.
value of X can be 0).
[0357] (2): While the drx-RetransmissionTimerUL is running, the UE
(100) shall monitor the downlink channel based on one or more of
below options:
[0358] (a): In an embodiment, when the drx-RetransmissionTimerUL is
running, the UE (100) monitors for the SSB transmission from the
base station (200). In further extension of this solution, the UE
(100) does not need to monitor for the SSB transmissions from the
base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) for which the DRX is configured.
[0359] (b): In another embodiment, when the
drx-RetransmissionTimerUL is running, the UE (100) monitors for any
CSI-RS transmission from the base station (200) corresponding to
the serving cell (if CSI-RS resources are configured to the UE
(100) for the serving cell). In further extension of this solution,
the UE (100) does not need to monitor for the CSI-RS transmissions
from the base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) for which the DRX is configured.
[0360] (c): In another embodiment, the UE (100) monitors for the
PDCCH identified by the cell common RNTI value (i.e. a predefined
RNTI value or RNTI value configured by the base station (200) e.g.
in system information or dedicated configuration). In further
extension of this solution, the UE (100) does not need to monitor
for PDCCH transmissions addressed to the cell common RNTI from the
base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) for which the DRX is configured.
[0361] (d): In another embodiment, the UE (100) monitors for a
preamble/any transmission from the base station (200) indicating
start/end/ongoing COT for the given serving cell of the base
station (200). In further extension of this solution, the UE (100)
does not need to monitor for preamble/any transmissions from the
base station (200) indicating start/end/ongoing COT, when the COT
is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) for the
DRX is configured.
[0362] (e): In another embodiment, the UE (100) monitors for the
PDCCH identified by the MAC entity's C-RNTI, CS-RNTI,
TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, and TPC-SRS-RNTI.
[0363] (3): After drx-RetransmissionTimerUL is started, the UE
(100) initializes a counter RETU-DRX-LBT-COUNTER=0
[0364] (4): On receiving the base station (200) indication of
unable to acquire channel using the long LBT, the UE (100) restarts
the drx-RetransmissionTimerUL (if running) and increments
RETU-DRX-LBT-COUNTER by 1.
[0365] (5): If RETU-DRX-LBT-COUNTER>MAX-REU-DRX-LBT-COUNTER (the
value can be configured by RRC), then the UE (100) performs the
RETU-DRX-LBT-FAILURE procedure.
[0366] (6): On successful reception of a DRX Command MAC CE or a
Long DRX Command MAC CE, the UE (100) shall stop
drx-RetransmissionTimerUL.
[0367] drx-RetransmissionTimerDL Operation:
[0368] (7): the UE (100) starts drx-RetransmissionTimerDL X time
units after drx-HARQ-RTT-TimerDL expires and if the data of the
corresponding HARQ process was not successfully decoded. Value of X
can be configured by the base station (200) (e.g. using system
information or dedicated configuration) or can be a predefined
value (e.g. value of X can be 0).
[0369] (8): While the drx-RetransmissionTimerDL is running, the UE
(100) shall monitor the downlink channel based on one or more of
below options:
[0370] (a): In an embodiment, when the drx-RetransmissionTimerDL is
running, the UE (100) monitors for the SSB transmission from the
base station (200). In further extension of this solution, the UE
(100) does not need to monitor for SSB transmissions from the base
station (200) when the COT is ongoing (e.g. based on dlCOTActive
and dlCOTInactive indications) for the given cell of the base
station (200) for which DRX is configured.
[0371] (b): In another embodiment, when the
drx-RetransmissionTimerDL is running, the UE (100) monitors for any
CSI-RS transmission from the base station (200) corresponding to
the serving cell (if CSI-RS resources are configured to the UE
(100) for the serving cell). In further extension of this solution,
the UE (100) does not need to monitor for the CSI-RS transmissions
from the base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) for which the DRX is configured.
[0372] (c): In another embodiment, the UE (100) monitors for the
PDCCH identified by the cell common RNTI value (i.e. a predefined
RNTI value or RNTI value configured by the base station (200) e.g.
in system information or dedicated configuration). In further
extension of this solution, the UE (100) does not need to monitor
for the PDCCH transmissions addressed to cell common RNTI from the
base station (200) when the COT is ongoing (e.g. based on
dlCOTActive and dlCOTInactive indications) for the given cell of
the base station (200) for which DRX is configured.
[0373] (d) In another embodiment, the UE (100) monitors for the
preamble/any transmission from the base station (200) indicating
start/end/ongoing COT for the given serving cell of the base
station (200). In further extension of this solution, the UE (100)
does not need to monitor for preamble/any transmissions from the
base station (200) indicating start/end/ongoing COT, when the COT
is ongoing (e.g. based on dlCOTActive and dlCOTInactive
indications) for the given cell of the base station (200) for DRX
is configured.
[0374] (e): In another embodiment, the UE (100) monitors for the
PDCCH identified by MAC entity's C-RNTI, CS-RNTI, TPC-PUCCH-RNTI,
TPC-PUSCH-RNTI, and TPC-SRS-RNTI.
[0375] (9): After drx-RetransmissionTimerDL is started, the UE
(100) initializes a counter RETD-DRX-LBT-COUNTER=0
[0376] (10): On receiving the base station indication of unable to
acquire channel using the long LBT, the UE (100) restarts the
drx-RetransmissionTimerDL (if running) and increments
RETD-DRX-LBT-COUNTER by 1.
[0377] (11): If RETD-DRX-LBT-COUNTER>MAX-RETD-DRX-LBT-COUNTER
(the value can be configured by RRC), then the UE (100) performs
the RETD-DRX-LBT-FAILURE procedure.
[0378] (12): On successful reception of the DRX Command MAC CE or a
Long DRX Command MAC CE, the UE (100) shall stop
drx-RetransmissionTimerDL.
[0379] UE Actions upon LBT Failure:
[0380] Random Access Response Timer Operation: In another
embodiment, Below actions taken by the UE (100) on random access
response reception failure because of excessive LBT failures or
RAR-LBT-FAILURE procedure--
[0381] (1): The UE (100) actions on the random access response
reception failure because of excessive LBT failures--
[0382] (a): In an embodiment, the UE (100) performs the same
procedure as ra-ResponseWindow expiry:
[0383] (i): the UE (100) increments PREAMBLE_TRANSMISSION_COUNTER
by
[0384] (ii): If PREAMBLE_TRANSMISSION_COUNTER=preambleTxMax+1, then
the UE (100) indicates random access problem to upper layers if the
PRACH is transmitted on SpCell or the UE (100) considers random
access procedure unsuccessfully completed if the PRACH is performed
on SCell.
[0385] (iii): If in this Random Access procedure, the Random Access
Preamble was selected by the MAC among the contention-based Random
Access Preambles, the UE (100) selects random backoff timer and
delays subsequent attempts by backoff value.
[0386] (iv): The UE (100) performs random access resource
selection.
[0387] (b): In another embodiment, on the RAR-LBT-FAILURE, the UE
(100) performs one or more of following actions:
[0388] (i): The UE (100) maintains a counter PREAMBLE_LBT_FAILURE,
such that at the beginning of random access procedure, the UE (100)
sets the value of PREAMBLE_LBT_FAILURE=1. Further, the UE (100) can
be configured with a parameter preambleLbtMax in random access
configuration.
[0389] (ii): If the UE (100) detects the RAR-LBT-FAILURE, the UE
(100) increments the PREAMBLE_LBT_FAILURE by 1
[0390] (iii): If PREAMBLE_LBT_FAILURE=preambleLbtMax+1, then the UE
(100) indicates random access problem to the upper layers if the
PRACH is transmitted on the SpCell or the UE (100) considers random
access procedure unsuccessfully completed if PRACH is performed on
SCell
[0391] (iv): If in this Random Access procedure, the Random Access
Preamble was selected by the MAC among the contention-based Random
Access Preambles, the UE (100) selects random backoff timer and
delays subsequent attempts by backoff value
[0392] (v): the UE (100) performs random access resource
selection.
[0393] (c): In another embodiment, the UE (100) does not increment
PREAMBLE_POWER_RAMPING_COUNTER if previous random access
transmission attempt resulted in RAR-LBT-FAILURE
[0394] (d): In another embodiment, the UE (100) de-prioritizes the
PRACH transmission using the given SSB/CSI-RS based RACH
Resources.
[0395] Contention Resolution Timer Operation: In another
embodiment, the actions taken by the UE (100) the on contention
resolution failure because of LBT failures or CR-LBT-FAILURE
procedure--
[0396] (1): The UE (100) actions on the random access response
reception failure because of excessive LBT failures--
[0397] (a): In one embodiment, the UE (100) performs the same
procedure as ra-ContentionResolutionTimer expiry.
[0398] (i): the UE (100) flushes the HARQ buffer used for
transmission of the MAC PDU in the Msg3 buffer;
[0399] (ii): the UE (100) increments PREAMBLE_TRANSMISSION_COUNTER
by 1
[0400] (iii): If PREAMBLE_TRANSMISSION_COUNTER=preambleTxMax+1,
then the UE (100) indicates random access problem to upper
layers.
[0401] (iv): the UE (100) selects random backoff timer and delays
subsequent attempts by backoff value.
[0402] (v): the UE (100) performs random access resource
selection.
[0403] (b): In another embodiment, on the CR-LBT-FAILURE, the UE
(100) performs following actions:
[0404] (i): the UE (100) maintains a counter PREAMBLE_LBT_FAILURE,
such that at the beginning of random access procedure, the UE (100)
sets the value of PREAMBLE_LBT_FAILURE=1. Further, the UE (100) can
be configured with a parameter preambleLbtMax in the random access
configuration.
[0405] (ii): If the UE (100) detects the RAR-LBT-FAILURE, the UE
(100) increments PREAMBLE_LBT_FAILURE by 1
[0406] (iii): If PREAMBLE_LBT_FAILURE=preambleLbtMax+1, then the UE
(100) indicates random access problem to the upper layers.
[0407] (iv): the UE (100) selects random backoff timer and delays
subsequent attempts by the backoff value
[0408] (v): the UE (100) performs the random access resource
selection.
[0409] (c): In another embodiment, the UE (100) does not increment
PREAMBLE_POWER_RAMPING_COUNTER if previous random access
transmission attempt resulted in the CONTENTION-LBT-FAILURE.
[0410] (d): In another embodiment, the UE (100) de-prioritizes the
PRACH transmission using the given SSB/CSI-RS based RACH
Resources.
[0411] sr-Prohibit Timer Operation: In another embodiment, the
actions taken by UE (100) for SR-LBT-FAILURE procedure.
[0412] (1): In one embodiment, the UE (100) triggers SR again and
increments corresponding SR_COUNTER by 1.
[0413] (2): In another embodiment, the UE (100) shall maintain a
SR_PROHIBIT_COT_FAIL_RETRY_COUNT,
[0414] (a): the UE (100) initializes
SR_PROHIBIT_COT_FAIL_RETRY_COUNT=0 when the SR is triggered for the
first time.
[0415] (b): For every, the UE (100) increments
SR_PROHIBIT_COT_FAIL_RETRY_COUNT by 1 every time
[0416] (a): SR-LBT-FAILURE procedure is run for the corresponding
SR.
[0417] (c): If
SR_PROHIBIT_COT_FAIL_RETRY_COUNT>SR_PROHIBIT_COT_FAIL_RETRY_COUNT_MAX
(which can be configured by RRC) then the UE (100) will trigger
corresponding SR again and increment SR_COUNTER by 1.
[0418] (3): In another embodiment, the UE (100) shall maintain a
SR_PROHIBIT_COT_FAIL_RETRY_COUNT,
[0419] (a): the UE (100) initializes
SR_PROHIBIT_COT_FAIL_RETRY_COUNT=0 when SR is triggered for the
first time.
[0420] (b): For every, the UE (100) increments
SR_PROHIBIT_COT_FAIL_RETRY_COUNT by 1 every time
[0421] (a): SR-LBT-FAILURE procedure is run for the corresponding
SR.
[0422] (c): If
SR_PROHIBIT_COT_FAIL_RETRY_COUNT>SR_PROHIBIT_COT_FAIL_RETRY_COUNT_MAX
(which can be configured by RRC) then the UE (100) will perform
RACH and steps similar to c when SR_COUNTER>=sr-TransMax.
[0423] periodicBSR-Timer Operation: In another embodiment, the
actions taken by the UE (100) for PERIODIC-BSR-LBT-FAILURE
procedure. When PERIODIC-BSR-LBT-FAILURE procedure is triggered the
UE (100) shall perform same actions as periodicBSR-Timer
expiry.
[0424] retxBSR-Timer Operation: In another embodiment, the actions
taken by the UE (100) for RETX-BSR-LBT-FAILURE procedure. When the
RETX-BSR-LBT-FAILURE procedure is triggered, the UE (100) shall
perform same actions as retxBSR-Timer expiry.
[0425] drx-onDurationTimer Operation: In another embodiment, when
the ON-DRX-LBT-FAILURE procedure is triggered, the UE (100) shall
stop drx-onDurationTimer if running.
[0426] drx-InactivityTimer Operation: In another embodiment, when
the IN-DRX-LBT-FAILURE procedure is triggered, the UE (100) shall
stop drx-InactivityTimer if running.
[0427] drx-RetransmissionTimerUL Operation: In another embodiment,
when the RETU-DRX-LBT-FAILURE procedure is triggered UE shall stop
drx-RetransmissionTimerUL if running.
[0428] drx-RetransmissionTimerDL Operation: In another embodiment,
when RETD-DRX-LBT-FAILURE procedure is triggered, the UE (100)
shall stop drx-RetransmissionTimerDL if running.
[0429] FIG. 3 is a flow chart S300 illustrating a method,
implemented by the base station (200), for handling the timer
operation in the wireless communication system (300), according to
the embodiments as disclosed herein. The operations (S302-S306) are
handled by the processor (210). At S302, the method includes
determining whether the COT is started or ongoing. In response to
determining that the COT is started or ongoing, at S304, the method
includes sending the COT active indication to the UE (100)
indicating that the base station (200) has acquired the COT for
transmission. In response to determining that the COT is not
started or ongoing at S306, the method includes sending the COT
inactive indication to the UE (100) indicating that the base
station has missed the transmission opportunity due to the LBT
failure.
[0430] FIG. 4 is a flow chart S400 illustrating a method,
implemented by the UE (100), for handling the timer operation in
the wireless communication system (300), according to the
embodiments as disclosed herein.
[0431] At S402, the method includes receiving the signaling message
from the base station (200). The signaling message includes the
information about acquired COT of the base station (200). At S404,
the method includes indicating about the acquired COT to the MAC
layer from the physical layer. The physical layer indicates that
the base station (200) acquires the COT for transmission or the
base station (200) has missed a transmission opportunity due to a
LBT failure.
[0432] The various actions, acts, blocks, steps, or the like in the
flow diagrams S300 and S400 may be performed in the order
presented, in a different order or simultaneously. Further, in some
embodiments, some of the actions, acts, blocks, steps, or the like
may be omitted, added, modified, skipped, or the like without
departing from the scope of the invention.
[0433] The embodiment disclosed herein can be implemented using at
least one software program running on at least one hardware device
and performing network management functions to control the
elements.
[0434] The foregoing description of the specific embodiments will
so fully reveal the general nature of the embodiments herein that
others can, by applying current knowledge, readily modify and/or
adapt for various applications such specific embodiments without
departing from the generic concept, and, therefore, such
adaptations and modifications should and are intended to be
comprehended within the meaning and range of equivalents of the
disclosed embodiments. It is to be understood that the phraseology
or terminology employed herein is for the purpose of description
and not of limitation. Therefore, while the embodiments herein have
been described in terms of preferred embodiments, those skilled in
the art will recognize that the embodiments herein can be practiced
with modification within the spirit and scope of the embodiments as
described herein.
* * * * *